bluuebunny/crossref_metadata_2025 huggingface dataset:
An approach to the coastal ocean acoustic tomography
Authors: Kaneko Arata , Zheng Hong , Noguchi Hideaki
Published: October 2005

A reciprocal sound transmission system has been designed for long-term current measurements in the coastal sea with heavy ship traffic and fishing activities. The system was composed of two acoustic stations spaced a distance of 5.7 km on both sides of a channel in the Seto Inland Sea, Japan. Each station was equipped with a transmitter, hydrophone, and GPS receiver. Reciprocal sound transmission experiments between the two stations were successfully completed for 5 h, using a carrier of 11 kHz, modified with the M sequence of 10th order. The time coordinate at both stations was synchronized with the accuracy of 0.1 μs by the 1-Hz and 1-kHz time signals of GPS. Range-averaged current velocities, estimated from the travel time data obtained reciprocally, were in good agreement with the results of the ADCP measurement obtained along the sound transmission line. A 10.6-km sound transmission experiment using the carrier of 11.0 kHz and the M sequence of 10th order was also done successfully in an adjacent channel of the Seto Inland Sea. The present sound transmission system can easily be extended to a coastal tomography system composed of an array of acoustic stations.
Observation of barotropic-tide relative vorticity in the northwest Atlantic
Authors: Dushaw Brian D. , Howe Bruce M. , Worcester Peter F. , Cornuelle Bruce D. , Metzger Kurt
Published: October 2005

Time series of reciprocal ray travel times were obtained at 350-, 410-, and 670-km ranges in the western North Atlantic during the 1991–1992 Acoustic Mid-Ocean Dynamics Experiment (AMODE). Transmissions were recorded for approximately 300 days between six transceivers in a pentagonal array. Barotropic current along each of the 15 propagation paths is derived from the difference of reciprocal ray travel times, while ten independent estimates of areal-averaged relative vorticity are found by integrating current around triangles in the pentagonal array. The estimated tidal currents are highly accurate, and tidal relative vorticity at the M2 frequency is detected. This vorticity is induced primarily by the stretching of vortex lines by tidal elevation. Harmonic constants (amplitude, phase) of M2 tidal vorticity are about (4–8±2×10−9 s−1, 270°−320° ±20°), while harmonic constants of about (2–3×10−9 s−1, 300°−340°) are predicted using the shallow-water equations. The measured tidal harmonic constants are compared with those derived from a global barotropic tidal model.
Acoustic observations of Mediterranean flow into the Black Sea
Authors: Di Iorio Daniela , Akal Tuncay
Published: October 2005

The physical behavior of the Mediterranean flow entering the Black Sea through the Bosphorus Strait is described using a variety of high-frequency acoustic systems. Because of the density difference between salty Mediterranean and fresh Black Sea water, a two-layer exchange is formed which is confined within a canyon in the Black Sea exit region of the Bosphorus Strait. A 307-kHz acoustical scintillation system placed 6 m from the seafloor and covering a 300-m propagation path is used to describe the mean Mediterranean current speed and the turbulent velocity fluctuations within the bottom boundary layer of the Mediterranean flow during a 4-day period when the exchange was maximal. In the idealized case of isotropic and homogenous turbulence, estimates of the turbulent kinetic energy dissipation rate leads to values ranging from 1×10−6 to 5×10−5 W/kg−1. A 600-kHz broadband acoustic Doppler current profiler placed within the canyon shows that the two-layer exchange displays temporal variability over scales of a few days associated with the meteorological conditions in the Black Sea. To help interpret the oceanographic measurements, a 120-kHz high-resolution echo sounder is used to obtain two-dimensional images of the two-layer exchange.
Sonic-boom noise penetration into the ocean: 1996 update
Authors: Sparrow Victor W. , Rochat Judith L. , Ferguson Tracie J.
Published: October 2005

Recently, there has been substantial progress in predicting the penetration of sonic boom noise into the ocean. Such noise penetration occurs for either commercial or military supersonic aircraft operating over the ocean. As previously discussed [J. Acoust. Soc. Am. 97, 3258(A) (1995)], one can use analytical techniques to make predictions of the noise penetration, but eventually finite difference calculations become the method of choice when accounting for wind wave swell and ocean inhomogeneities. Two-dimensional calculations already indicate that typical wind wave swell can focus or defocus a penetrating rounded sonic boom waveform up to approximately ±1.5 dB for a homogeneous ocean below a homogeneous atmosphere. Higher Mach number supersonic flight accentuates the focusing. Predictions are currently being sought for more realistic sonic boom waveform shapes, three-dimensional interactions between the incident boom and the ocean swell, and the effects of bubble plumes immediately below the ocean surface. One simulation of the focusing from ocean swell will be visualized via a videotape. [Work supported by NASA Langley Research Center, under Grant NAG 1–1638, and by Armstrong Laboratory, Air Force Material Command, USAF, under Grant F41624–96–1-0003.]
Reduction of noise radiated from supersonic jets
Authors: Umeda Yoshikuni , Ishii Ryuji
Published: October 2005

In the present investigation, sound-pressure levels radiated from the twin- and multijet with a square configuration were measured at various pressure ratios R from 2.00 to 6.33. The nozzle diameter was 5 mm and the center-to-center spacing of the nozzles was fixed to 1.4 times the nozzle diameter. From this experiment, it is found that the overall sound-pressure level (OASPL) radiated from the multijet with a square configuration becomes lower than that from the twin jet for the pressure ratio range R≳4.0. In the near sound field upstream of the nozzle exit, the difference of the OASPL between the twin- and multijet with a square configuration reaches a maximum (about 7 dB) at the pressure ratio about R=5.0. This decreasing of the OASPL may be caused by the shielding of the sound waves radiated from the inner part of the multijet with a square configuration by the surrounding four jets, and by stabilizing the jet oscillation due to the appropriate coupling process among four jets. [Work supported by the Ministry of Education and Culture of Japan (Grant No. C2-08650201).]
Exact solutions for sound radiation from a circular duct with flows
Authors: Cho Y. C.
Published: October 2005

Sound radiation from a circular duct is a classic problem. Exact solutions were previously reported for the case of a negligibly thin duct wall, using the Wiener–Hopf technique. Despite the elegance of its closed-form solutions, the numerical presentations have been limited to mere demonstrations of its capability. A computer program is not publicly available for its numerical evaluation. Such a numerical evaluation has recently become increasingly in demand not only for its own merits, but also for cross examination of the numerical results of computational aeroacoustics. These techniques are just starting to attract widespread attention as a potential tool in attacking important but unsolved aeroacoustic problems. This paper presents a comprehensive mathematical procedure for the numerical evaluation primarily for use in studies of noise emission of aircraft engines. Various mean flows are included for simulations of an aircraft jet engine exhaust and inlet, and aircraft cruise condition. Unlike previously published reports, this paper will include radiation of nonpropagating modes as well as propagating modes.
Lord Rayleigh revisited: Can vortices in tubes be sources of noise?
Authors: Lee James B.
Published: October 2005

Energy can flow through tubes filled with air governed by the laws of fluid dynamics, even in the violent form of shock waves. Energy also can flow through such systems as oscillations of small amplitude, which are governed by the equations of linear acoustics. What happens in the regime between? Calculations performed upon complaint of excessive low-frequency noise during alternate blasting for two long parallel railway tunnels indicated that particle velocities were a substantial fraction of the speed of sound at the tunnels’ mouths—between the regimes of shock waves and linear resonances. A Strouhal calculation suggested that vortices were the likely source: A sequence of counter-rotating vortices was being propelled out of the tunnels’ mouths, generating a powerful monopole source at 12 Hz. Modern noise consultants were baffled, but Lord Rayleigh had solved the system a century before, as a compound nonlinear eigenvalue problem, necessarily taking viscosity into account. The blasting engineers drove small cross-bores between the tunnels, sucking circulating fluid out of the vortices, reducing power, and quieting neighbors. The experiment should be repeated at a smaller scale with better instruments under controlled conditions.
Sound energy distribution at an intersection of an underground tunnel: Additional small-scale experiments
Authors: Imaizumi Hiroyuki , Kunimatsu Sunao , Isei Takehiro
Published: October 2005

In studies on some interactions between sound propagation characteristics and environmental factors underground, small-scale experiments on the sound energy distribution at an intersection of tunnels have been carried out in an anechoic room. The small-scale tunnels were made by acrylic plates, and the original surfaces of inner walls were assumed to have an acoustically hard condition, while surfaces of the walls covered by flannel were acoustically soft. Impulsive sound was generated electrically as a sound source was applied, and propagated sounds were measured by an omnidirectional microphone. The experiments were carried out under several kinds of conditions for angles at the intersection and positions of the sound source. Influences of intersection on the sound energy distribution were indicated by comparisons between the measuring points before and behind the intersection with different angles. In addition, the influences of the acoustical characteristics of the inner walls and positions of the source are also presented.
Nonlinear surface wave propagation in a piezoelectric material
Authors: Hamilton M. F. , Il’inskii Yu. A. , Zabolotskaya E. A.
Published: October 2005

Model equations were derived from first principles for nonlinear surface wave propagation in a piezoelectric material. There is no dependence on ad hoc or empirical parameters. The present work extends an earlier analysis of surface waves in crystals, described by the authors at the previous meeting [J. Acoust. Soc. Am. 99, 2538(A) (1996)]. As in the earlier work, the model equations account for crystals having arbitrary symmetry, and for surface wave propagation in arbitrary directions in planes having arbitrary orientations with respect to the crystalographic axes. Here, elastic, piezoelectric, dielectric, and electrostrictive properties of the material are taken into account. The model is formulated as spectral evolution equations that are integrated numerically to illustrate the distortion of a finite amplitude surface wave that is sinusoidal at the source. The material we considered is LiNbO3, for which measured values of all required second- and third-order elastic constants are available in the literature [e.g., the latter are reported by Cho and Yamanouchi, J. Appl. Phys. 61, 875 (1987)]. Analysis of the nonlinearity matrix permits identification of which physical effects contribute most to the distortion of nonlinear surface waves. [Work supported by ONR, NSF, and Schlumberger Foundation.]
Second harmonic generation in a sound beam transmitted through an isotropic solid
Authors: Landsberger B. J. , Hamilton M. F. , Il’inskii Yu. A. , Zabolotskaya E. A.
Published: October 2005

An ultrasonic immersion procedure for determining third-order elastic coefficients of rock via measurements of harmonic generation was described recently by Plona et al. [ J. Acoust. Soc. Am. 98, 2886(A) (1995)]. Here an accurate quasilinear model is presented for second harmonic generation in a sound beam transmitted through an isotropic solid immersed in liquid. With the primary beam represented as an angular spectrum, analytic solutions were derived for second harmonic generation by all pairs of plane waves in both the liquid and the solid. Numerical superposition of the analytic solutions, followed by Fourier transformation, yields the second harmonic field anywhere in the solid or liquid. There are no restrictions on geometry or orientation of the sound source, and all combinations of compression and shear wave interactions are taken into account. At the previous meeting the accuracy of this model for the case of reflection near the Rayleigh angle was demonstrated [J. Acoust. Soc. Am. 99, 2538(A) (1996)]. Reported here are comparisons with second harmonic diffraction patterns that were measured in a 1-MHz beam radiated by a 1.2-cm radius source and transmitted through a 10-cm-thick block of lucite immersed in water. [Work supported by ONR, NSF, and Schlumberger Foundation.]
Observations of nonlinearity with slow dynamics in rocks
Authors: TenCate James A. , Shankland Thomas J. , Johnson Paul A. , Zinszner Bernard
Published: October 2005

A typical resonance curve—measured acceleration versus drive frequency—made on a thin bar of rock shows peak bending with a softening (nonlinear) modulus as drive levels are increased. Previous work showed the shapes of these nonlinear resonance curves depend on sweep rate, i.e., the ‘‘slow dynamics.’’ Slow dynamics in a 0.3-m-long, 50-mm-diam bar of Berea sandstone under ambient conditions have been documented for the first time. Peak strain levels during the experiments ranged from 10−11 to 10−5 at a fundamental bar resonance frequency near 4 kHz. Slow dynamics begin to appear at strain amplitudes above 10−6 at ambient conditions and at the onset of nonlinear peak bending. Higher strains condition the rock, altering its response for minutes to hours after the drive has been turned off. Other rocks show similar results. Physical origins of the slow dynamics lie in nonlinear effects at the microstructural level of cracks, pores, and interstitial clays. Further work examines environmental effects on conditioning and recovery as a means of relating them to physical properties and microtexture of the rock. [Work supported by OBES/DOE through the University of California.]
The role of within-category structure in the integration of auditory and visual speech
Authors: Hall Michael D. , Smeele Paula M. T. , Kuhl Patricia K.
Published: October 2005

The influence of visual information on auditory speech perception can be observed under conditions where the two sources of information are discrepant. One demonstration involves viewing a face producing /b/ while listening to a dubbed /g/ token, with participants reporting that they heard /bg/ (McGurk and MacDonald, 1976). This ‘‘combination’’ response reflects the contribution of both modalities. Two experiments evaluated whether differences in the perceived quality of auditory stimuli within the /g/ category influence the incidence of combination responses. Synthetic VCV stimuli ranging from ‘‘good’’ /aga/ to ‘‘poor’’ /aga/ tokens were generated by factorially combining 6 levels of F2, and 4 levels of F3, onset frequency. In experiment 1 participants identified these auditory stimuli and rated them with respect to goodness as a /g/. Goodness was found to be correlated with, but not completely predicted by, consonant identification. In experiment 2 these stimuli were separately dubbed with a visual /aga/ (‘‘matched’’) and /aba/ (‘‘mismatched,’’ which should evoke combination responses). Results will be discussed in terms of the sufficiency of consonant identification and category goodness in predicting the probability of combination responses. These data will be used to address models of auditory-visual speech integration. [Work supported by NICHD.]
Audiovisual integration of speech based on minimal visual information
Authors: Whalen D. H. , Irwin Julia , Fowler Carol A.
Published: October 2005

Two competing theories have been proposed to explain the fact that vision can dominate over audition in syllables that have been spliced so that the two modalities specify different phonemes [McGurk and McDonald, Nature 263, 746–748 (1976)] . The first theory states that acoustic and visual information are combined in varying proportions depending on how strong the information is in each signal. The second proposes that the visual signal has linguistic value because speech gestures can be conveyed visually, and that these gestures are the primitives of speech perception for every modality. The present experiment contrasts dynamic and static visual information by reducing the visual signal to two or three video frames, synchronized with the speech in the appropriate location. Dynamic stimuli had at least two frames showing movement of the mouth, while static ones had a single frame, taken from the consonant closure, repeated to make a three frame visual image. Even these brief images were enough to elicit speech percepts that matched the visual image. The dynamic and static images were equally effective, suggesting revisions in both theories. [Work supported by NIH Grant No. HD-01994.]
Relationships between word knowledge and visual speech perception. I. Subjective estimates of word age of acquisition
Authors: Auer Edward T. , Waldstein Robin S. , Tucker Paula E. , Bernstein Lynne E.
Published: October 2005

In individuals with normal hearing, words estimated to be learned earlier are recognized more rapidly than words estimated to be learned later. To investigate how word knowledge is related to lipreading proficiency, word age-of-acquisition (AOA) estimates were obtained from 50 hearing (H) and 50 deaf (D) (80-dB HL pure-tone average or greater hearing losses acquired before the age of 48 months) adults. Participants judged AOA for the 175 words in Form M of the Peabody Picture Vocabulary Test-Revised using an 11-point scale, and responded whether the words were acquired through speech, sign language, or orthography. The two groups differed in when (mean AOA: H = 8.9 years, D = 10.6 years) and how (H=69% speech and 31% orthography; D=38% speech, 45% orthography, and 17% sign language) words were judged to be acquired. However, item analyses revealed that the relative acquisition order was essentially identical across groups (r=0.965). Interestingly, within the deaf group, better lipreaders estimated that more words had been learned through speech than orthography. An implication of these results is that learning words primarily through orthography does not support highly accurate spoken language processing. [Work supported by NIH Grant No. DC00695.]
Speechreading talking faces
Authors: Massaro Dominic W. , Campbell Christopher S. , Berger Michael A. , Cohen Michael M.
Published: October 2005

It is now well established that visible speech is an important source of information in face-to-face communication. Given the valuable role of audible speech synthesis in experimental, theoretical, and applied arenas, visible speech synthesis has been developed. Research has shown that the talking head closely resembles real heads in the quality of its speech and its realism (when texture mapping is used). The talking head can be heard, communicates paralinguistic as well as linguistic information, and is controlled by a text-to-speech system. Several sources of evidence are presented which show that visible speech perception (speechreading) is fairly robust across various forms of degradation. Speechreading remains fairly accurate even when the mouth is viewed in noncentral vision; eliminating and distorting high-spatial frequency information does not completely disrupt speechreading; and speechreading is possible when additional visual information is simultaneously being used to recognize the speech input. The results are consistent with the fuzzy logical model of perception in which multiple sources of information are used to recognize patterns. Various visible feature sets are tested within the framework of the model to determine which visible features are functional in speechreading. Demonstrations of the talking head and various psychological phenomena will be provided. [Work supported by NIDCD.]
Sensitivity of cued speech reception to cue imperfections
Authors: Bratakos Maroula S. , Braida Louis D.
Published: October 2005

In manual cued speech (MCS) a speaker gestures with his/her hand to resolve ambiguities among speech elements that are often confused by speechreaders. The shape of the hand distinguishes among consonants, and the position of the hand relative to the face distinguishes among vowels. Experienced receivers of MCS achieve nearly perfect reception of everyday connected speech. To understand the benefits that might be derived from the imperfect cues produced by an automatic cueing system, videotaped sentences with handshapes corresponding to the phones identified by simulated phonetic speech recognizers were dubbed. The cues dubbed on these sentences were discrete in both shape and position rather than fluidly articulated, and the speaking rate was roughly 50% faster than for MCS. When the phones identified by an ideal recognizer were used to produce the cues, performance was only slightly lower than for MCS. When cues were derived from an existing recognizer, intelligibility was reduced, but substantial benefits to speechreading were observed. Current research is aimed at developing an automatic speech recognition system with the speed, accuracy, and computational efficiency required for a real-time automatic cueing system. [Work supported by NIH.]
Hemispheric differences in perceiving and integrating dynamic visual speech information
Authors: Johnson Jennifer A. , Rosenblum Lawrence D.
Published: October 2005

There is evidence for a left-visual-field/right-hemisphere (LVF/RH) advantage for speechreading static faces [R. Campbell, Brain & Cognit. 5, 1–21 (1986)] and a right-visual-field/left-hemisphere (RVF/LH) advantage for speechreading dynamic faces [P. M. Smeele, NATO ASI Workshop (1995)]. However, there is also evidence for a LVF/RH advantage when integrating dynamic visual speech with auditory speech [e.g., E. Diesch, Q. J. Exp. Psychol.: Human Exp. Psychol. 48, 320–333 (1995)]. To test relative hemispheric differences and the role of dynamic information, static, dynamic, and point-light visual speech stimuli were implemented for both speechreading and audio–visual integration tasks. Point-light stimuli are thought to retain only dynamic visual speech information [L. D. Rosenblum and H. M. Saldaña, J. Exp. Psychol.: Human Percept. Perform. 22, 318–331 (1996)]. For both the speechreading and audio–visual integration tasks, a LVF/RH advantage was observed for the static stimuli, and a RVF/LH advantage was found for the dynamic and point-light stimuli. In addition, the relative RVF/LH advantage was greater with the point-light stimuli implicating greater relative LH involvement for dynamic speech information.
Cross-modal context effects on the perception of /r/ and /l/ in a speech and nonspeech mode
Authors: Green Kerry P. , Norrix Linda W.
Published: October 2005

Norrix and Green [J. Acoust. Soc. Am. 99, 2591–2592 (1996)] provided evidence for cross-modal context effects on the perception of /r/ and /l/ in a stop cluster. Tokens from a synthetic /iri–ili/ continuum were dubbed onto a visual /ibi/. When presented in an auditory-visual (AV) condition, the tokens were perceived as ranging from /ibri/ to /ibli/. Results indicated a reliable shift in the AV condition relative to an auditory-only (AO) condition. This shift was in accord with acoustic consequences of articulating /r/ and /l/ in a stop cluster. In the current study, sine-wave analogs of the /iri–ili/ tokens were constructed and presented to two groups of observers in an AO and AV condition. Group One was told they would hear schematic speech sounds and instructed to identify what they heard as /r/ or /l/. Group Two made up their own criteria for classifying the tokens as nonspeech sounds. Results indicated a reliable shift in the /r–l/ boundary between the AO and AV conditions for the speech group only and suggest that the influence of the visual articulatory context depends upon listeners interpreting the auditory tokens as speech. [Work supported by NIDCD, NIH.]
Effect of sign complexity on speech timing in simultaneous communication
Authors: Whitehead Robert L. , Schiavetti Nicholas , Whitehead Brenda , Metz Dale Evan
Published: October 2005

Simultaneous communication combines spoken English with manual representations of English words by signs and fingerspelling. The purpose of this investigation was to study the effect of sign complexity on temporal features of speech during simultaneous communication (SC). The effects of three independent variables: (a) mode (speech only versus SC); (b) sign complexity (base versus elaborated signs); and (c) type of sign movement (kinetic versus morphokinetic) were studied on five dependent variables: (a) word duration, (b) sentence duration, (c) diphthong duration, (d) interword-interval before signed experimental word (IWIB), and (e) interword-interval after signed experimental word (IWIA). Audio recordings were made of 12 normal-hearing, experienced sign language users speaking experimental words that varied in sign complexity and movement under SC and speech only (SO) conditions. Results indicated longer sentence durations for SC than SO and longer anticipatory durations of IWIB and diphthong before signed words, especially those using more complex signs. IWIA only lengthened for SC vs SO with no further effect of sign complexity. These results indicate a finite effect of sign complexity on pause and segment durations before the sign but not as strong an effect as has been reported for increased fingerspelling complexity.
Neural processes of audio–visual speech perception
Authors: Imaizumi Satoshi , Mori Koichi , Kiritani Shigeru , Yumoto Masato , Seki Hideaki
Published: October 2005

Neural processes related to audio–visual speech perception were investigated by measuring the mismatch magnetic fields (MMF), which reflect a neural activity detecting deviant stimuli randomly inserted in a stream of rapidly repeating frequent stimuli. Three audio–visual stimuli were used: AbVg (audio signal /ba/ with discrepant visual signal /ga/), AbVb, and AdVd. MMF were measured from the left hemisphere of 16 normal hearing subjects using a 37 ch SQUID magnetometer. The rate of non-/ba/ responses to AbVg (McGurk fusion effect) varied depending on the stimulus condition and subjects. It was 80% when AbVg was the frequent, but was 45% when AbVg was the deviant. Significant MMF-like fields were excited in the auditory cortex by deviant AbVg embedded in frequent AbVb. The subjects with a low-fusion rate had larger MMF-like fields than those with a high rate. These results suggest that the auditory mismatch detection process is affected by visual signal, and phonetic categorization is affected by a module which can either fuse or dissociate audio–visual information.
‘‘SLIP-ing’’ in phonologically similar neighborhoods
Authors: Vitevitch Michael S.
Published: October 2005

Phonological speech errors are the class of speech errors in which one or more phonemes are added, deleted, substituted, or reversed. Previous work [Dell (1990); Stemberger and MacWhinney (1986)] has found that low-frequency words are more likely to be involved in phonological speech errors than high-frequency ones. If word frequency, influences performance in speech production, do other characteristics of words, such as neighborhood density or neighborhood frequency, influence speech production? The influence of phonologically similar neighborhoods on a type of whole word speech error (malapropisms) has previously been demonstrated [Vitevitch (1996)]. The present research examined the influence of phonologically similar neighborhoods on phonological speech errors. Using the SLIPS technique [Motley and Baars (1976)], phonological speech errors were elicited from participants with real word pairs that varied in their neighborhood characteristics. The results show that low-frequency words ‘‘slipped’’ more often than high-frequency ones, replicating past results from error corpora and from other studies using this methodology. Moreover, words with sparse phonologically similar neighborhoods tended to ‘‘slip’’ more than words with dense phonologically similar neighborhoods. The implications for these findings on models of speech production, speech perception, and lexical representation are discussed.
Effects of phonotactic probability on segmentation of words in continuous speech
Authors: Gaygen Daniel E. , Luce Paul A.
Published: October 2005

The role of phonotactic probability in the segmentation of spoken words in continuous speech was investigated. Participants made speeded word detection responses to sequences of spoken stimuli composed of target words preceded and followed by nonwords (i.e., NONWORD–TARGET WORD–NONWORD). Speed and accuracy of detection were examined as a function of the nonword contexts of the target words. In particular, probabilities of segmental transitions from the nonword contexts to the target words were manipulated: Pairs of segments composed of the last segment of the preceding nonword and the first segment of the target word—as well as pairs composed of the last segment of the target word and the first segment of the following nonword—were varied in terms of intraword transition probability (HIGH and NONE) and transition type (CC, CV, VC, and VV). Both intraword co-occurrence probabilities and transitional probabilities were manipulated. The implications of the results for the use of phonotactic probabilities in the identification of words in fluent speech will be discussed.
Sources of variability as linguistically relevant aspects of speech
Authors: Nygaard Lynne C. , Burt S. Alexandra
Published: October 2005

Recent research has suggested that only linguistically relevant sources of variability, or those which affect the perception of spoken words, are retained in long-term memory. The present study sought to determine if the linguistic relevance of surface characteristics such as speaking rate, overall amplitude, and vocal effort would differentially affect memory retention. For each source of variability, a continuous recognition memory task was used in which listeners were presented with a list of spoken words and asked to judge whether each word in the list was ‘‘old’’ (had occurred previously on the list) or ‘‘new.’’ Results showed that listeners were better able to identify a word as ‘‘old’’ if the word was repeated at the same speaking rate (condition 1), overall amplitude (condition 2), or vocal effort (condition 3), suggesting that the individual surface characteristics which comprise each type of variability were encoded into memory. However, speaking rate and vocal effort produced a greater effect on recognition memory than overall amplitude, indicating that all sources of variability may not be processed and encoded to the same extent. Rather, memory for surface characteristics may be related to the amount of linguistically relevant information each source of variability contains.
Young children’s and older adults’ sensitivity to semantic and pragmatic context in speech production
Authors: Charles-Luce Jan , Dressler Kelly M.
Published: October 2005

It is generally expected that speakers of American English neutralize the /t/-/d/ voice contrast in words like ‘‘writer’’ and ‘‘rider’’ and instead produce them as homonyms. However, it has been demonstrated that young adults adjust their articulation depending on context and do not always neutralize this contrast. In particular, young adults preserve the voice contrast in semantically biasing contexts and when speaking for a listener. In the present investigation, the interest was in determining when young children became sensitive to semantic and pragmatic context and, consequently, when they adjusted their articulation in ways similar to young adults. Moreover, there was interest in older adults’ sensitivity to context. Young children (ages 7–12), young adults (college age), and older adults (ages 60–80) produced minimal pairs containing voiced and voiceless intervocalic alveolar stops in two semantic contexts (biasing and neutral) and in two pragmatic contexts (listener-present and -absent). The results showed developmental changes in speakers’ sensitivity to semantic and pragmatic contexts. These results will be discussed in terms of interactive activation, involving the structure and organization of a speaker’s linguistic system, and pragmatic compensation, involving a speaker’s cognitive decision processes to adjust articulation for the listener’s benefit. [Work supported by NIH.]
The role of lexical access in spontaneous speech disfluencies
Authors: McRoberts Gerald W. , Clark Herbert H.
Published: October 2005

Pauses and hesitations in spontaneous speech are assumed to result from problems in various aspects of sentence planning. A causal role for difficulties with lexical access is suggested by theoretical accounts of speech production [Levelt, Speaking (1989)] and empirical studies showing that pauses are more likely before rare than common words in spontaneous speech [Maclay and Osgood (1959)]. In the present study, word frequency was manipulated in a picture-naming task in which speakers produced the names of ten high- and ten low-frequency pairs of standardized line drawings within a standard sentence frame (e.g., There is a snail to the left of the harp.). The mean frequency of occurrence for high- and low-frequency items was 171.5 (range: 50–591) and 3.5 (range: 1–8) per million, respectively [H. Kucera and W. N. Francis, A Computational Analysis of Present-day English (1967)]. Analyses indicate that low-frequency pairs resulted in: (1) more pauses and word substitutions and (2) longer latencies to begin speaking.
Effects of discourse structure on F0 in Japanese: Raising versus lowering
Authors: Venditti Jennifer J.
Published: October 2005

Previous studies on English and other languages have shown that discourse structure has an influence on the intonation of a string of sentences or phrases. With respect to fundamental frequency in particular, both discourse-initial raising of F0 and final lowering effects have been reported. The present study examines whether discourse structure also influences intonation in Japanese, and if so, to what extent initial raising and final lowering interact to cue structure. Hierarchically organized discourses were constructed in which the target sentence position was varied. These short discourses were recorded by native speakers of Tokyo Japanese, and the fundamental frequency contours of the target sentences in each position were compared. Results indicate that there is a robust raising effect on discourse-initial phrases, as reported for other languages. The degree of raising is determined by an interaction between distance from the start of the utterance and pitch range. In contrast, there is little effect of lowering on discourse-final phrases. The few phrases that did show an effect suggest that syntactic structure may interact with the lowering process.
Identification, vocal rating, and acoustical measurement of acted emotion
Authors: Strong William J. , Brown Bruce L. , Spackman Matthew P. , Wang Rong , Feldstein Stanley
Published: October 2005

A series of studies of eight acted emotions compared acoustical measurements, respondents’ identifications, and vocal ratings. Predictions were made as to which of these three approaches would be most accurate in differentiating between emotions within a pair. Emotion pairs were classified as logically similar and/or perceptibly similar. Logically similar emotion pairs (such as sadness/depression or anger/hate) were better distinguished by vocal/acoustic analysis. Perceptibly similar but logically dissimilar emotions (such as anger, fear, and joy) were better distinguished by respondents’ identifications. Multivariate statistics were used to compare the respondents’ identification space, and vocal rating space, and the acoustical measurement space.
Linguistic strategies in the first 6 months of life
Authors: Lacerda Francisco , Sundberg Ulla
Published: October 2005

The ability to detect word contrasts embedded in natural sentences was studied with 62 Swedish infants whose ages ranged from 48 to 147 days, using the high-amplitude sucking (HAS) technique. The infants listened to one of four possible pairs of natural carrier sentences, produced as child-directed speech, in which a target word was inserted: (1) a pair of sentences in which the contrasting target words was inserted in focal position; (2) a pair of sentences in which the target words were out of the sentence focus; (3) a pair of sentences that differed only in the position of the sentence focus; and (4) a control pair with two identical sentences. When this group of subjects is divided into two age groups, one below and the other above the median age for all the subjects, a pattern of interaction between the age groups and the experimental conditions is observed suggesting that word discrimination capacity in the younger infants may be disrupted by dominantF 0 variations. For the older group, a tendency to attend to the word contrasts delivered in focal position seems to start to emerge. [Research supported by The Bank of Sweden Tercentenary Foundation, Grant No. 94-0435.]
Contrastive emphasis in elicited dialogue
Authors: Erickson Donna , Lehiste Ilse
Published: October 2005

Phrase level characteristics of F0 and their interactions with duration patterns for a set of contrastively emphasized digits in elicited dialogues are examined. Phrases consisting of three digits plus a street name were elicited in a dialogue format designed to have the speaker repeat the same correction on one of the digits up to five or six times. Perception tests determined which phrases where ‘‘best perceived’’ and ‘‘worst perceived’’ as to emphasis. Onset, offset, and peak F0 within the sonorant portion of each digit of those phrases ‘‘best perceived,’’ ‘‘worst perceived,’’ and the reference phrases, with no corrective emphasis, were measured. Results suggest that speakers produce well-perceived contrastive emphasis by lengthening the duration of the emphasized word, shortening the duration of the other words within the phrase, and producing an extensive pitch drop between the emphasized word and the following words in the phrase. In an elicited dialogue situation in which the speaker is forced to produce repetitively the same item with contrastive emphasis, different combinations of these two cues are used, presumably in an attempt to maximize the chance that emphasis will be perceived.
Social influence on the phonemic transformation effect
Authors: Hinsz Verlin B. , Chalikia Magdalene H. , Matz David
Published: October 2005

Earlier studies found that repeated sequences of brief steady-state vowels are heard as verbal forms, a phenomenon referred to as the phonemic transformation effect (PTE). It has also been established [Chalikia et al., J. Acoust. Soc. Am. 91, 2422(A) (1992)] that, when two listeners’ responses differ, they can identify the particular stimulus corresponding to each other’s verbal forms. Other research suggests that unclear stimuli can be influenced by social forces. The present study examined social influences on the PTE. Participants were first asked to describe their verbal forms for ten vowel sequences used in previous studies. Then they were presented with verbal forms reported by previous listeners and were asked to match them to the ten stimuli. Most listeners performed the matching task, indicating that they could perceptually reorganize each stimulus. Finally, they were asked to listen to the sequences again and describe their verbal forms. About 47% of these responses corresponded to those provided by previous listeners, indicating that social information influenced some of the second responses to these stimuli. Implications concerning the perceptual interpretation of speech and social impact theory will be discussed.
Feasibility of implementing near-field acoustic holography at large scale
Authors: Carroll Gerard P.
Published: October 2005

This paper presents the results of a numerical investigation into the technical feasibility of implementing near-field acoustic holography (NAH) at large scale. Results are presented using both numerically generated hologram plane pressures for ka<4.0, as well as measured hologram plane pressures for a small scale ribbed cylindrical model (ka<20). The focus of the investigation is to determine whether or not large scale implementation of NAH is feasible given the magnitude of background noise levels and sensor placement inaccuracies likely to be encountered. Background noise for various lake and ocean environments are considered. The effect of both random and systematic axial, circumferential and radial sensor placement errors is assessed and compared. The majority of the results are presented as wave number comparisons of contaminated and uncontaminated surface pressure reconstructions. In general, the effects of data contamination are evident in these comparisons as high wave number noise. It is shown for these simulations that the success of implementing NAH at large scale relies largely on the selection of a low-pass wave number filter with a cutoff frequency suitable for removing these contaminating factors while preserving the cylinder’s actual wave number response. [Work supported by ONR.]
Holographic reconstruction in the interior space using the boundary element method
Authors: Ih Jeong-Guon , Kim Bong-Ki
Published: October 2005

The BEM-based acoustic holography is applied to predicting vibroacoustic parameters on the boundary enclosing the interior space. The singular value decomposition method is utilized for inverse operation of the transfer matrix. Such backward reconstruction usually suffers from the divergence phenomenon due to the inversion of ill-conditioned matrix produced by nonradiating wave components involved with extremely small measurement errors. In order to minimize the reconstruction error arising from the divergence phenomenon, optimal measurement positions are determined by the effective independence method. In addition, regularization methods are used to enhance the resolution of reconstructed field by suppressing the nonradiating wave components. The interior field of a rectangular box is considered as an example for validating and demonstrating the proposed reconstruction process and the experimental verification is carried out. It is noted that the present method can effectively improve the resolution of the reconstructed field, thus vibroacoustic parameters on the vibrating boundary can be estimated with reasonably good precision.
Near-field acoustic holography measurements of the acoustic radiation from violins
Authors: Wang Lily M. , Burroughs Courtney B.
Published: October 2005

As previously described, an open-frame mechanical bowing apparatus has been constructed to excite a violin [L. M. Wang and C. B. Burroughs, J. Acoust. Soc. Am. 99, 2502(A) (1996)]. An array of microphones is mounted to this apparatus on each of the six sides of the frame, boxing the violin source. Complex pressure measurements made in the near field of the violin are then used with a modified near-field acoustic holography (NAH) algorithm. Results characterizing the three-dimensional sound radiation field around a violin using the above setup are presented and discussed. [Work supported by NSF and an AT&T GRPW Grant.]
Experimental observations of Anderson localization by disorder on a framed fluid-loaded cylinder
Authors: Houston Brian H. , Photiadis D. M. , Bucaro J. A.
Published: October 2005

The presence of internal structure can greatly alter the acoustic behavior of elastic systems. Many structures of interest are comprised of reinforced shells where a periodic placement of the stiffeners lead to well-known stop- and passbands for the long-range transport of vibrational energy. Various degrees of disorder are typically the norm in real systems and the phenomenon of localization can dominate the structural dynamics and lead to high degrees of apparent damping even for frequencies well inside passbands. Generally speaking, localization can result from a number of physical mechanisms that include: radiation damping, structural damping, local resonances, and Anderson localization. Experiments have been conducted on a 1.02-m-long stainless steel cylindrical shell with 80 ring stiffeners attached with a small degree of irregularity in their placement (on average δz/d is ±2.5). Out-of-plane structural velocities in the midfrequency band were derived by employing nearfield acoustic holography (NAH) for the case of radial point excitation. The experimental evidence of Anderson localization on a fluid-loaded two-dimensional system is reported here for the first time. [Work supported by NRL and ONR.]
Visualization of a surface wave in an elastic medium via the complex Poynting vector
Authors: Dean Cleon E. , Braselton James P.
Published: October 2005

The complex Poynting vector can be used to visualize not only the flow of energy in an elastodynamic solid, but also the wave itself passing through the elastic medium. Usually the time average of the Poynting vector over one cycle is obtained, but this only gives the time average of the energy flux through the medium. However the instantaneous elastodynamic Poynting vector can be used instead of the more usual time-averaged Poynting vector in order to follow the energy flow as a function of time. The instantaneous Poynting vector gives the instantaneous energy flux through the elastic medium. The imaginary part of the complex Poynting vector gives the difference in the peak rates at which energy is stored in the medium at that point. This has already been shown for the simpler case of the instantaneous Poynting vector in an acoustic medium [J. A. Mann III et al., J. Acoust. Soc. Am. 82, 17–30 (1987)]. Computer animations of the instantaneous Poynting vector for a Rayleigh surface wave in a variety of materials, as well as the real and imaginary parts of the complex time averaged vector field, will be shown.
Modeling of glottal flow between oscillating walls with a computer fluid dynamics method
Authors: Alipour Fariborz , Scherer Ronald C.
Published: October 2005

Computational fluid dynamics (CFD) was used to obtain numerical solutions to laryngeal flow between simulated vibrating vocal folds. The unsteady Navier–Stokes equations were solved with a finite volume method using a nonuniform staggered grid. Vocal fold motion was simulated by sinusoidal variation of the inferior and superior glottal widths. The straight glottal walls oscillated between converging and diverging shapes, and the input airflow was sinusoidally varied from zero to a maximum and back to zero. Control variables included frequency of oscillation, Reynolds number, minimum glottal diameter, and the phase difference between the inferior and superior sections of the glottis. Results will be reported for Reynolds numbers of 1000 to 2000 and for oscillation frequencies of 100 to 200 Hz. Results with preliminary simulations (for which the glottal entry was fixed) produced periodic velocity and pressure fields throughout the whole laryngeal duct, and dominant effects of the flow acceleration and convection terms of the Navier–Stokes equations on the pressure gradient term. [Work supported by NIDCD Grant No. DC00831-04.]