bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration sensation in played stringed instruments
Authors: Jansson Erik V. , Askenfelt Anders
Published: October 2005

The vibration levels in four traditional stringed instruments during playing have been investigated, including the double bass, violin, guitar, and the piano. The vibration levels, which were measured at several positions and at different dynamic levels, were evaluated with respect to reported thresholds for detection of vibrotactile stimuli. The results show that the vibration levels are well above threshold for almost all positions of the instruments in normal playing. It is concluded that the perceived vibrations may be of some assistance with regard to intonation in ensemble playing, in particular for the bass instruments. The finger forces exerted when playing the bowed strings, as well as the touch forces in piano playing were studied briefly. It was concluded that the kinestetic forces perceived in playing may assist the timing in performance. [Work supported by the Swedish Council for Research in the Humanities and Social Sciences.]
The role of tactile and kinesthetic feedback in speech production
Authors: Harris Katherine S.
Published: October 2005

Since sensory-motor integration is a central topic in studies of limb movement, one might expect studies of the role of kinesthesis and taction to have a central role in one’s understanding of the motor organization of speech production. However, perhaps because of the lack of a fully adequate animal model for speech, or because of the inacessibility of the articulators to experimental manipulation, the literature is quite limited. This paper will review existing experimental studies, as they fall under four headings: (1) the effect of reduction of tactile and kinesthethetic feedback from the articulators; (2) the effect of experimental static alteration of the relationship among the articulators, such that feedback from them is altered during articulation; (3) the effect of transient mechanical perturbation of articulation; (4) comparison of the role of taction and kinesthesis in the speech of normals and individuals with severe and profound hearing impairment, for whom auditory feedback cannot have its normal role in speech acquisition. [Work supported by NIDCD.]
Tactile and auditory measures of modulation resolution
Authors: Rabinowitz W. M. , Reed C. M. , Delhorne L. A. , Besing J. M.
Published: October 2005

Limited signals derived from speech can provide effective supplements to speechreading. For a single-band speech envelope that is used to modulate a 200-Hz tone, the benefit to speechreading is, however, greater with auditory than tactile presentation. Is this due to differences between hearing and touch in the psychophysical ability to perceive amplitude modulation changes? Experiments are being conducted to assess amplitude modulation discrimination as a function of reference modulation depth (m=0 to 1) and modulation frequency (fm=5 or 50 Hz). Carrier frequency is fixed at 200 Hz and stimulus presentation is via headphone for audition and a minishaker for taction. Preliminary results indicate that, on average, auditory thresholds for Δm are roughly 6 dB more sensitive than tactile thresholds. These results extend those previously available in the literature by considering cases of nonzero reference values for m, which may be particularly relevant to the information that is conveyed in the single-band speech envelope. [Work supported by NIDCD.]
Experimental system identification of the interior acoustic field of a business aircraft
Authors: Gibbs G. P. , Fuller C. R. , Mahnken B. W. , Ralston H. H.
Published: October 2005

This paper presents the results of a series of tests measuring the acoustic response of a Cessna Citation 3 fuselage. For all tests the acoustic response was measured using 90 Metravib microphones mounted in an array spanning the cross section of the aircraft. The array was scanned axially using a computer controlled system along the aircraft interior providing the response at 2790 locations. In the first test, excitation was provided by a point force shaker oriented radially and located at the left side engine pylon. The input force was measured using a PCB force transducer. During the second test, an acoustic driver mounted in the nose of the aircraft was used as the excitation. The paper will discuss the results of the system identification, including a comparison of the results of a modal analysis technique with those obtained using a two-dimensional Fourier transform technique.
Active control of plate volume velocity using shaped PVDF sensor
Authors: Guigou C. , Berry A. , Charette F.
Published: October 2005

The radiated sound power of a planar structure is related to the velocity distribution over the surface of that structure. The well-radiating velocity distributions have in general a nonzero volume velocity. A PVDF sensor design strategy is presented for applications in active structural acoustic control (ASAC). It is based on the modal representation of the response of the studied finite simply supported plate. It consists in designing a PVDF sensor composed of several PVDF strips bonded to the surface of the structure in such a way that the output signal of the sensor is directly proportional to the volume velocity of the vibrating simply supported finite plate. This sensor detects only contributions from the odd–odd modes, being the only ones with a nonzero volume velocity as well as being the most effective radiators. Experimental implementation of such a PVDF volume velocity sensor will be discussed. The efficiency of this type of sensor in ASAC will be analytically evaluated as the far-field radiated acoustic power, the quadratic velocity as well as the radiation efficiency before and after control will be extensively studied. The advantage of this active control approach (minimization of volume velocity) is that only one error sensor is used in the control process.
A case study in university–industry cooperation on active sound and vibration control research
Authors: Eriksson L. J. , Allie M. A. , Greiner R. A.
Published: October 2005

This paper will review the history of a successful university–industry cooperative research program, and its role in the history of active sound and vibration control. In 1981, the corporate research department of a manufacturer of passive silencing products approached a major research university for assistance on a research program in the emerging field of active sound and vibration control. Developments in digital signal processing at that time suggested that the technology, invented in the 1930s, had the potential for successful application. A joint research program was initiated with the university to support research to advance the technology. Company personnel continued their own complementary research and also participated in university activities including taking courses and pursuing graduate degrees. The result of these combined efforts was the development of significant new solutions to old problems. Ultimately, the manufacturer formed a new business unit to commercialize these advances in a variety of markets and applications. The company continues a major research and development program in active sound and vibration control, and a number of former students are now employees at the company. Cooperative research activities with the university also continue.
Active control using only a layer of simple sources
Authors: Fahnline John B. , Koopmann Gary H.
Published: October 2005

Previous research in the area of active noise control has shown that the sound radiation from a vibrating body can be completely controlled using layers of simple and dipole sources located on a surface that completely surrounds the vibrating body. If complete control of the sound radiation could be achieved with simple sources only, the implementation of the control strategy will be considerably simplified because simple sources can be approximated with conventional loudspeakers. It is shown that complete control can be achieved when the simple source layer is very near the boundary surface of the vibrating body (assuming that the fluid coupling between the vibrating body and the surrounding fluid is negligible). When the simple source layer is not near the surface of the vibrating body, the control strategy fails at the resonance frequencies of the volume of fluid between the surface of the vibrating body and the layer of simple sources. The effect of approximating the continuous source distribution by a discrete source distribution is examined, and it is shown that the discrete sources can control the sound radiation effectively as long as there are an adequate number of sources distributed over the surface of the vibrating body.
Use of perforated panels as an active control source
Authors: Hansen Colin H. , Burgemeister Kym A.
Published: October 2005

The use of active vibration control of a thin perforated panel consisting of a closely packed array of holes to reduce noise radiated from a vibrating structure is examined. The advantages of using a perforated panel are that it allows natural cooling of machinery while providing a high level of noise control and it only requires small control forces on the panel to control the noise from heavy structures. The acoustic interaction between the perforated control panel and the radiating primary structure is shown to be negligible, allowing a simple dual source control arrangement to be considered. This model allows more accurate prediction of controlled sound levels to be made compared to previous models that have assumed constant pressure between the primary structure and perforated control panel. [Work Supported by AESIRB.]
Active control of energy density in three-dimensional enclosures
Authors: Sommerfeldt Scott D. , Parkins John
Published: October 2005

Attenuating the sound pressure at a microphone in an enclosure typically results in a relatively small region of control, often referred to as a zone of silence. In an effort to increase the region of control for practical applications, as many as 30–50 microphones have been used to achieve a broader region of control. An alternative control method for achieving global control of the field, based on sensing and minimizing the total energy density at discrete locations, has been developed. Previous work using this method in one-dimensional enclosures has indicated that significant improvement in overall attenuation is possible. This improvement can be attributed to the fact that sensing the energy density monitors all of the modes of the enclosure, and thereby avoids the spillover problem which often plagues control systems that minimize only pressure. The work reported here extends the energy density approach to three-dimensional, rectangular enclosures. Numerical results are presented to compare the global attenuation achieved by minimizing the energy density and acoustic pressure at single and multiple discrete locations. These results are also compared with the control that one would achieve by minimizing the total potential energy in the enclosure.
Fundamental frequency effects on thresholds for vowel formant discrimination
Authors: Kewley-Port Diane , Li Xiaofeng , Zheng Yijian , Beardsley Amy Neel
Published: October 2005

In a recent report, thresholds for discrimination of vowel formants are described as a piecewise-linear function that is flat in the F1 region and linearly increasing in the F2 region [Kewley-Port and Watson, J. Acoust. Soc. Am. 95, 485–496 (1994)]. Results also suggested a trend for higher fundamental frequency to produce increased formant thresholds for these synthetic female vowels. Further study of the effect of various stimulus parameters on formant thresholds is needed to describe discrimination using excitation pattern models. The present experiment investigated the effect of glottal source on formant thresholds in synthesized male vowels. Thresholds for formant-frequency discrimination were obtained for six vowels with two fundamental frequencies: High (126 Hz) and low (101 Hz). Four well-trained subjects performed an adaptive tracking task under minimal-uncertainty conditions. Discrimination thresholds for vowels with high F0 were significantly greater than those with low F0. Consistent with results for female vowels, thresholds for frequencies below 800 Hz in the F1 region appeared relatively constant while thresholds in the F2 region were increasing. There was a general trend across all male and female vowels for higher fundamental frequency to result in increased discrimination thresholds. [Research supported by NIDCD and AFOSR.]
Perception of linear formant trajectories in vowels
Authors: Nabelek Anna K. , Ovchinnikov Alexandra
Published: October 2005

Boundary locations for identification functions were tested for /i-eh/ and /u-i/ continua. In the /i-eh/ continuum, F1 varied in 14 steps from 360 to 580 Hz, and in the /u-i/ continuum, F2 varied in 19 steps from 1000 to 2000 Hz. There were five different types of stimuli in each continuum with (1) steady-state formants, (2) one formant changing linearly over time, and (3) two formants changing linearly. The single changing formant was F1 in the /i–eh/ continuum and F2 in the /u–i/ continuum. The two changing formants were F1 and F2 in both continua. The trajectories had upward or downward directions. Identification functions were obtained with ten normal-hearing subjects. Directions of boundary shifts for the /i–eh/ continuum indicated a perceptual emphasis of the initial segments of F1 and F2 trajectories. The directions of boundary shifts for the /u–i/ continuum indicated a perceptual emphasis of the final segment of F2 trajectory when only F2 changed over time. However, when changes over time in F1 were added, boundaries for these stimuli were not significantly different from the boundary for the stimuli with steady-state formants. Differences in perception of F1 and F2 trajectories in two tested continua will be discussed. [Work supported by NIH.]
Single formant discrimination as a function of F1–F0 Bark distance
Authors: Hughes Dennis L. , Diehl Randy L.
Published: October 2005

Hoemeke and Diehl [J. Acoust. Soc. Am. 93, 2422(A) (1993)] reported that the perceptual boundary between [+high] and [−high] English vowels occurs at an F1–F0 distance of 3–3.5 Bark and that this boundary is sharper than those for other height contrasts. This suggests that the 3- to 3.5-Bark distance, corresponding to the range of the ‘‘center of gravity’’ effect [L. Chistovich and V. Lublinskaja, Hear. Res. 1, 185–195 (1979)], affords a perceptually natural boundary. In the current study, listeners performed a 0.5-Bark step F1–F0 discrimination task on one of five series of single formant stimuli. F1 ranged from 2.5–7.0 Bark within a series, and F0 ranged from 1.0–2.0 Bark between series. Significant linear effects of both a formant/harmonic interaction (r=0.68) and F1–F0 distance (r=0.71) were found (multiple R2=0.94). However, a peak in discriminability near F1–F0=3–3.5 Bark was not observed. Thus the relatively sharp [+high]/[−high] boundary does not appear to be owing to enhanced discriminability. [Work supported by NIDCD.]
Prosodic constraints on glottalization of vowel-initial syllables in American English
Authors: Dilley Laura , Shattuck-Hufnagel Stefanie , Ostendorf Mari
Published: October 2005

Earlier work on the glottalization of vowel-initial syllables sought an account in terms of the morphosyntactic hierarchy and isolated intonational facts, without accounting for the possible role of prosodic constituent structure. In a corpus of digitized, prosodically labeled speech (FM radio news style, 371 vowel-onset syllables produced by a single female speaker), (a) a syllable which begins in intonational constituent and is pitch accented is likely to show a glottal onset (91%), (b) constituent-initial position and pitch accent each separately increase the likelihood of glottal onset (66% and 47%, respectively). Noninitial nonaccented syllables are much less likely to be glottalized (16%; some of these syllables may have a pitch accent that is small in comparison with the strongly realized accents often produced in FM news speech). Constituent-initial glottalization occurs even for reduced-vowel syllables, which earlier work suggested was rare: 83% of reduced-vowel syllables in constituent-initial position glottalized, but only 24% in noninitial position. Preliminary results for a second speaker show a similar pattern, illustrating both the value of revisiting earlier analyses with prosodic structure in mind, and the usefulness of a large prosodically labeled database of continuous speech.
Effects of speaking rate and paragraph structure on the production of sentence prosody
Authors: Speer Shari R. , Wayland Sarah C. , Kjelgaard Margaret M. , Wingfield Arthur
Published: October 2005

Four speakers read each of eight paragraphs at four different speaking rates: Normal speaking rate and half, twice, and three times the normal rate. Each paragraph contained five sentences, one each of five types of syntactic structure: Early major syntactic break, early minor syntactic break, late major syntactic break, late minor syntactic break, or syntactic break midway through the sentence. Across paragraphs, sentences of the same syntactic type had the same prosodic foot structure, and the order of syntactic structures within paragraphs was counterbalanced. Care was also taken to make the paragraphs semantically coherent. Phonetic analyses of the prosodic structures produced for these paragraphs are presented, including absolute and relative duration measures for words and silences. In addition, listener judgments of perceived prosodic phrasing are presented. Results will be compared to the durational and pausing patterns predicted by current prosodic production algorithms (Ferreira, 1993; Gee and Grosjean, 1983). Prosodic variation due to speaking rate, syntactic structure, and paragraph structure will be discussed. [Order of authorship determined by multiple coin flips.]
Synthesizing multistyle speech using the Klatt synthesizer
Authors: Lambert Daniel , Cummings Kathleen , Rutledge Janet , Clements Mark
Published: October 2005

Synthesizing multistyle speech has been an important topic of research in recent years. In this research, 11 commonly encountered speech styles have been synthesized by varying pitch, duration, intensity, and the glottal excitation on the Klatt Synthesizer 88, KLSYN88. These 11 speech styles include angry, clear, 50% tasking, 70% tasking, fast, Lombard, loud, normal, question, slow, and soft. All of the styles proved to be intelligible and appropriately styled based on subjective listening tests. The parameter variations of the glottal excitation are based on the results of statistical analyses [K. Cummings, Analysis, Syn., and Rec. of Stressed Speech, Ph.D thesis, Georgia Inst. of Tech., 1992] that demonstrated the importance of glottal excitation changes in styled speech. These statistical analyses demonstrated that the glottal excitation of each of the eleven styles is significantly and identifiably different. One utterance of the work ‘‘hot’’ was synthesized in the normal style. The other ten styles of this word were synthesized by changing only the glottal excitation parameters of the normal utterance. Subjective listening tests with untrained subjects demonstrated that the eleven synthetic styles were perceivably and identifiably different.
Simulations and efficient prediction of matched-field processing degradation from mismatch in shallow water
Authors: Ozard John M. , Yeremy Maureen L. , Price Mariner A.
Published: October 2005

Mismatch between the replica and the measured fields in matched-field processing can result in a significant loss in detection and localization performance. Such mismatch effects may be estimated through computer intensive simulations. When this was done for vertical line arrays in Pacific and Arctic shallow water environments with typical uncertainties from conventional bathymetry and sediment sound-speed measurements, substantial mismatch effects were found. It is also possible to predict, with minimal calculation, the nature and, in some cases, the relative magnitude of mismatch effects. Simulated mismatch effects for both horizontal and vertical line array configurations in different shallow water environments agreed well in magnitude and nature with the predictions for environmental or geometric mismatch. Environmental mismatch studied included bathymetry and sound-speed errors while geometric mismatch included Doppler effects and array tilt. A consistent relationship was found between the degradation of the match at the true source location and the predictor. Different relationships were found for the best match on the ambiguity surface and the match at the true source location. The predictor was then employed to show how mismatch increases with frequency.
Localization of a moving source in oceanic waveguide using a vertical array in the presence of correlated noise
Authors: Song Hee Chun , Seong Woojae
Published: October 2005

In a recent paper, matched-field processing (MFP) for localizing a point acoustic source using a vertical array in an oceanic waveguide was extended to treat a moving source problem in the presence of both spatially and temporally white Gaussian noise process. The spatially white noise assumption, however, is not realistic for MFP because noise as well as signal propagates in the ocean obeying the governing wave equation, such as the noise field generated by the action of wind. In this paper an optimum processor is developed for passive localization of a moving source in the presence of correlated noise using normal mode description of the sound field. The approach involves a preliminary processing to transform the problem into a white Gaussian noise problem, followed by applying the white Gaussian noise solution.
Matched-field tracking of acoustic sources in shallow water
Authors: Bucker Homer
Published: October 2005

A simple matched-field tracking algorithm is proposed for transit detection of acoustic sources in shallow water. Let A and B represent the end points of a track. A track correlation function, CAB, is calculated using the formula CAB= ∑f∑t{(Re ∑lγlγ̂*l) /[(∑lγlγ̂*l) (∑γ̂lγ̂*l)]}. In the equation above, the indices f, t, and l are for different frequencies, time periods, and sensor pairs, respectively, and the * denotes complex conjugate. The term γ is the short period time average of the j,k element of the covariance matrix. That is, γl=〈FjF*k〉, where Fj is the signal received at sensor j. In a similar manner, γ̂l=〈F̂jF̂*k〉, where Fj is the expected field if the acoustic source followed the track AB. Realistic simulations will be shown for detection of sound sources by a vertical line of sensors in a shallow water area with a sloping bottom.
Matched-field processing and source depth localization in a shallow-water environment (SWellEX-1)
Authors: Schey P. , Ryan F.
Published: October 2005

During 2 weeks in August 1993, a high-fidelity acoustic experiment, SWellEX-1, was conducted in shallow waters off San Diego, CA. The SWellEX-1 site is a 50 to 200-m bottom-limited shallow-water environment characterized by strong range dependence in both bottom and water column properties. Calibrated broadband and tonal signals from a projector in the band 70–750 Hz were received on a 48-channel, 90-m aperture vertical line array (VLA) spanning the lower half of the water column. Source tows are depths from 15–100 m were conducted along isobaths and up-slope relative to the VLA. Results of source depth localization using plane-wave processing (omega-k plots) and matched-field tracking will be presented. Depth localization via matched-field processing with high-fidelity replica vectors generated using both range-dependent and range-independent models will be compared. The impact of bottom geoacoustic properties ‘‘mismatch’’ on matched-field processing will be discussed. [Work supported by ONR under NRaD block CS3A.]
Adaptive estimation of acoustic normal mode amplitudes
Authors: Wage Kathleen E. , Baggeroer Arthur B.
Published: October 2005

The normal mode amplitudes and their second-order statistics are useful in understanding sound propagation in the medium and for matched-mode processing (MMP) and matched-field tomography (MFT). Standard modal beamforming techniques introduce a least-squares error criterion to compute the modal amplitude estimates. This work uses a method of adaptive estimation which is capable of processing both coherent and incoherent modes. The new approach is fundamentally different from other modal estimators (e.g., MMP) because it is data-adaptive and maximizes SNR against an ambient noise background instead of minimizing squared error in the estimate without regard to the noise. The new methods are studied using simulations which include coherent and incoherent modes and a realistic ocean noise model. The performance of the estimators is evaluated with respect to the following criteria: (i) orthogonality of the sampled mode shapes, (ii) power level and spatial structure of the noise, (iii) mode coherence, (iv) modeling assumptions (number of modes to estimate), and (v) the presence of multiple modal sources. The new methods perform significantly better than least squares in high noise environments and in situations where the sampled modes are not orthogonal.
Scalar measures of modal amplitude distributions in range-dependent waveguides
Authors: Orchard B. J. , Cooper D. K.
Published: October 2005

In a shallow water waveguide with a depth-dependent sound velocity profile, the short-range modal amplitude distribution depends strongly upon the sound-speed profile at the source. At sufficiently high frequency, a source in the high-velocity portion of the water column excites primarily the higher-order modes while a source in the lower-velocity portion of the water column couples more strongly with the lower-order modes. Scalar measures, such as the correlation, cross-entropy and information divergence are used in this paper to differentiate between different modal amplitude distributions by projecting the cross-spectral density matrix (CSDM) onto the eigenvectors of a baseline CSDM. Environmental features which cause mode coupling (e.g., bottom slope) diminish the effectiveness of these measures. The robustness of these scalar measures in the presence of the mode coupling is examined. [Work sponsored by Office of Naval Research, Code 4530.]
The multivalued Bartlett processor and source tracking
Authors: Collins Michael D. , Fialkowski Laurie T. , Kuperman W. A. , Perkins John S.
Published: October 2005

The MUSIC method [R. O. Schmidt, Ph.D. dissertation, Stanford Univ. (1981)] and other beamformers based on covariance matrix eigenvectors suppress sidelobes and provide high resolution. These methods exploit the fact that energy arriving from sources located in different directions tends to partition into different eigenvectors. Eigenvector processors have been less successful for matched-field applications because of the prevalence of environmental uncertainty and the sidelobe structure of matched-field ambiguity surfaces. The multivalued Bartlett processor, which involves applying the Bartlett processor to the eigenvectors corresponding to the largest eigenvectors, is less sensitive to mismatch than high-resolution eigenvector processors. The well-defined estimates of the source locations correspond to the locations of the peaks in the ambiguity surfaces for the different eigenvectors. Since the sidelobes in matched-field ambiguity surfaces are distributed, energy partitioning is not necessarily favorable for sources in different locations. The multivalued Bartlett processor is effective for moving sources, however, because the partitioning is likely to be favorable for randomly selected locations. As the sources move, the partitioning may be favorable frequently enough for the source paths to be come evident. a)Present address: Scripps Institution of Oceanography, La Jolla, CA 92093.
Active, wideband detection in an uncertain multipath environment
Authors: Wazenski M. , Alexandrou D.
Published: October 2005

Active, wideband detection of targets in a dense multipath environment is approached via optimal detection and estimation theory in conjunction with a received signal model described by weighted and delayed replicas of the transmitted signal. The set of weights and delays are known to vary with acoustic medium properties including sound-speed profile, bottom composition and topography and surface area, which are largely unknown or uncertain. The optimum receiver is based on prior distributions of multipath amplitude and delay. An acoustic propagation model drives the optimum receiver by generating these distributions through Monte Carlo simulation. Unlike traditional matched field techniques, the acoustic medium is treated as a random process rather than a deterministic one for a given set of propagation conditions. The sonar system toolset (SST)/generic sonar model (GSM) software package provides the required simulation environment. Illustrative detection examples are presented along with receiver operator characteristic (ROC) performance. [Work supported by Digital System Resources.]
Active, wideband detection of spherical elastic objects of uncertain composition
Authors: Wazenski M. , Alexandrou D. , Nolte L. W.
Published: October 2005

Active, wideband detection of solid, elastic, spherical objects is approached via optimal detection and estimation theory in conjunction with accurate acoustic modeling. This approach incorporates the inherent uncertainty of critical object parameters, which vary as a function of temperature, pressure, and purity. Robust detection is especially important due to the high sensitivity of scattered fields to these varying parameters, examples of which include size, density (object and medium), compressional wave speed (object and medium), and shear wave speed. The signal model employed assumes that incident signals undergo a spatial and spectral filtering operation which is accurately described by the acoustic model. Detection is limited to spherical objects in white isotropic noise. Illustrative detection examples are presented along with receiver operator characteristic (ROC) performance. [Work supported by ONR, Ocean Acoustics.]
Salient pitch cues in the perception of contrastive focus
Authors: Bartels Christine , Kingston John
Published: October 2005

The distinction between contrastive and noncontrastive focus in English can be conveyed by the difference between a L+H* vs H* pitch accent [Pierrehumbert and Hirschberg, in IntentionsinCommunication, edited by Cohen etal. (MIT, Cambridge, MA, 1990)]. It is unclear, however, which acoustic properties of an F0 contour convey to a listener the occurrence of the contrastive L+H* rather than the noncontrastive H*. In these experiments, rise onset F0, peak F0, and slope were varied to see how they alone and together contribute to the contrast between a L+H* vs H* on the focused constituent. Listeners classified the stimuli as either contrastive or noncontrastive, with discourse context distinguishing the two interpretations. Peak height and slope traded in determining the category boundary between interpretations. Implications for the choice of primitives in intonational models and for compositional approaches to tune meaning are discussed. [Work supported by NIH.]
On the interaction of phonology and orthography in spoken word recognition
Authors: Soltano Emily G. , Slowiaczek Louisa M.
Published: October 2005

The interaction of phonology and orthography in spoken word recognition was examined in experiments using lexical decision and shadowing tasks. The first syllable of primes and targets shared phonology (FERTILE-FURNISH), orthography (BUGLE-BUGGY), both (PICKLE-PICTURE) or neither (PENGUIN-FELLOW). In addition, the first syllable of the target could constitute a word (RATIFY) or a nonword (DERANGE). A standard lexicality effect was obtained in lexical decision (i.e., words were responded to faster than nonwords). Also, a first syllable lexicality effect was obtained in lexical decision and shadowing, replicating earlier work [E. A. Lyons and P. A. Luce, J. Acoust. Soc. Am. 93, 2372 (1993)]. For word targets, orthography facilitated response times relative to phonology and both phonology and orthography in shadowing and lexical decision. For nonword targets and nonword first syllables, phonology facilitated response times relative to orthography and both phonology and orthography. These results contrast with those obtained by Jakimik etal. [J. Mem. and Lang. 24, 165–178 (1985)] in which facilitation was obtained only for both phonology and orthography. The current results suggest that words and nonwords are differentially influenced by phonological and orthographic cues. [Work supported by NIH grant NS-29286-03.]
The time course of neighborhood and lexical effects in phoneme identification
Authors: Newman Rochelle , Sawusch James R. , Luce Paul
Published: October 2005

Previously, results were presented suggesting that neighborhood density could have effects similar to those of lexical status in phoneme identification tasks. In a typical task demonstrating a lexical effect, subjects might hear two series, one ranging from ‘‘bag’’ to ‘‘pag,’’ while the other varied from ‘‘pal’’ to ‘‘bal.’’ Subjects were more likely to classify the ambiguous stimuli from each series as members of the category which makes a word (they would classify ambiguous items as ‘‘b’’ in the bag-pag series but as ‘‘p’’ in the pal-bal series). In a similar task where none of the four endpoints were words, it was found that subjects classified the ambiguous items as members of the category which had a greater neighborhood density. Variability in previous lexical reports of effects may have been caused by these neighborhood differences. The results of new experiments will be reported that examined neighborhood effects with lexical items and lexical effects without neighborhood differences, along with a framework for a model that explains these effects and their timecourse. [Work supported by NIDCD Grant No. DC00219 to SUNY at Buffalo and an NSF Graduate Fellowship to the first author.]
Perceptual normalization of speech and nonspeech
Authors: Pitt Mark A.
Published: October 2005

Within the information processing approach to speech perception, the problem of acoustic-phonetic variability is solved by positing multiple stages of processing that transform the acoustic input into a stable phonetic percept. If this problem is viewed as part of the broader problem of perceptual normalization, a question that arises is whether the mechanisms that normalize speech stimuli also normalize nonspeech stimuli. Five experiments addressed this question by investigating the normalization of musical timbre using a selective adaptation paradigm. The results parallel some of those found with speech, suggesting that a single mechanism normalizes both types of stimuli.
Evaluation of a dynamical model of speech perception
Authors: Case Pamela , Tuller Betty , Ding Mingzhou , Kelso J. A. S.
Published: October 2005

Previous work [Tuller etal., JEP:HPP (in press)] revealed signature properties of nonlinear dynamical systems in how people categorize speech sounds. The data were modeled using a two-well potential function that deforms with stimulus properties and is sensitive to context. The model predicts an increase in the rate of change of the slope of the potential with increased repetitions of a percept. Thus the slope of the potential corresponding to a given physical stimulus should be steeper (and stability indexed by judged goodness should be greater) when the stimulus is presented at the end of a sequence than at the beginning. Similarly, the same physical stimulus presented near the middle of a sequence with few (or no) stimuli between them should show no such differences. In the present experiment stimuli from a ‘‘say’’–‘‘stay’’ continuum were presented sequentially with gap duration first increasing, then decreasing. The eight S’s had to identify each token and to rate how good an exemplar it was of the perceived category. Results confirmed model predictions, further supporting the hypothesis of a context-sensitive dynamical representation underlying speech.
Tests of the perceptual magnet effect for American English /k/ and /g/
Authors: Davis Katharine , Kuhl Patricia K.
Published: October 2005

Recent experiments from this laboratory suggest that the perceptual organization of vowel categories is strongly influenced by category goodness. Perceptual distances appear to be ‘‘shrunk’’ near best exemplars and ‘‘stretched’’ near worst exemplars. The present experiments extend these findings to consonant categories, specifically, American English /k/ and /g/. Fifteen variants of /k/ and /g/ were synthesized by independently changing voice onset time and aspiration amplitude. Adult native speakers gave goodness ratings on a seven-point scale for individual tokens and similarity ratings on a seven-point scale for pairs of these tokens. Multidimensional scaling analyses demonstrated that the perceptual space was shrunk near the best instances of these categories, primarily along the voice onset time dimension. Results were especially strong for the /k/ category, demonstrating clear within-category differences between best and worst exemplars. This suggests that the perceptual magnet effect will characterize consonant perception as well as vowel perception. Studies currently being conducted on additional cues to velar stop goodness will also be discussed. [Work supported by NIH.]
Tests of the perceptual magnet effect for American English /r/ and /l/
Authors: Iverson Paul , Kuhl Patricia K.
Published: October 2005

Experiments by Kuhl and her colleagues have suggested that the perceptual organization of vowel categories is strongly influenced by category goodness. Using a variety of techniques, including signal detection analysis and multidimensional scaling, a perceptualmagneteffect for vowels characterized by poor sensitivity and perceptual clustering near the best exemplars of a category and by good discrimination and stretched perceptual distances near the worst exemplars has been demonstrated. The present experiments extend these findings to American English /r/ and /l/. Sixteen variants of /r/ and /l/ were synthesized by independently changing F2 and F3. Adults gave similarity ratings on a seven-point scale for pairs of these tokens. Multidimensional scaling analyses demonstrated that the perceptual space was shrunk in the F2 and F3 dimensions near the best exemplars of /r/ and /l/, and that the perceptual space was stretched in both dimensions near poor exemplars. This suggests that the perceptual magnet effect may characterize the perception of liquid consonants as well as vowels. Additional experiments on the perception of American English /r/ and /l/ by nonnative speakers may also be discussed. [Work supported by NIH.]
Fundamental frequency effects on [voice] judgments in intervocalic stop consonants
Authors: Castleman Wendy A. , Diehl Randy L.
Published: October 2005

Fundamental frequency (F0) has been found to affect judgments of the [+voice]/[−voice] distinction in initial consonants. The present study examined the influence of F0 contour on [voice] judgments of intervocalic consonants. Sixteen /aba/–/apa/ series, each varying in medical closure duration, were synthesized with different F0 contours. Each contour was defined by the F0 value, either 95 or 110 Hz, at four temporal points: First syllable onset, onset of closure, onset of voicing after closure release, and second syllable offset. F0 transitions before or after closure lasted 70 ms. Results showed that both steady-state and transitional portion of the F0 contour influenced [voice] judgments, and that F0 cues in the initial syllable had larger and more reliable effects than those in the final syllable. In general, the lower the F0 value at a given temporal point in the disyllable, the greater the percentage of [+voice] judgments. [Work supported by NIDCD.]
Decision strategies in information integration
Authors: Weber Daniel L. , Sanger Stephen P.
Published: October 2005

In separate conditions, four listeners discriminated samples from distributions of the duration of a 1-kHz sinusoid and from distributions of the frequency of a 100-ms sinusoid in a 2IFC, sample-discrimination procedure. For duration discrimination, the ‘‘standard’’ distribution (100-ms mean) was discriminated from an ‘‘easy’’ comparison (140-ms mean) distribution and from a ‘‘hard’’ comparison (110-ms mean) distribution. For frequency discrimination, the ‘‘standard’’ distribution (1000-Hz mean) was discriminated from an ‘‘easy’’ comparison (1400-Hz mean) distribution and a ‘‘hard’’ comparison (1010-Hz mean) distribution. Standard and comparison distributions were normal with standard deviations set to the difference in their means so that all conditions yielded a d′ of 1.41 for an ideal observer. Pooled (all n samples from a given distribution presented in succession) and paired (one sample from each distribution presented in n successive pairs) presentation structures were tested for these four combinations of standard and comparison distributions. Information integration, represented by the increase in d′ as a function of the number of samples (n=1, 2, 3, 4, 5, 6, 8, 12, and 16), was examined in all eight conditions. Pooled presentations uniformly led to better performance. The partitioned-variance model and the decision-combination model were used to represent different strategies for information integration in these data. [Research supported by a grant from AFOSR through WPAFB AL/CFBA.]
Human versus ideal performance on a three-interval forced-choice task with stimulus uncertainty along one and two dimensions
Authors: Mackersie Carol , Boothroyd Arthur
Published: October 2005

Discrimination of sinusoids was measured using a three-interval forced-choice ‘‘sample-discrimination’’ paradigm in which mean values of target and nontarget stimuli remain fixed but individual stimuli are selected from Gaussian distributions. The task was designed as a psychoacoustic analog of an existing three-interval forced-choice test of phonetic contrast perception. Performance of five human subjects was measured as a function of d′ and compared with that of an ideal observer. In three experiments, stimuli differed in terms of frequency alone, intensity alone, and both. Performance on the unidimensional frequency and intensity discrimination tasks was very similar. It approximated the ideal for very high and very low values of d′ but fell below the ideal for intermediate values (6≳d′≳3). This finding suggests a shift from a post- to a preclassification decision strategy as stimulus uncertainty increases. When uncorrelated uncertainties of frequency and intensity were introduced in the two-dimensional task, performance of the ideal observer improved, as expected, but that of the human observers did not. This finding suggests a tendency to attend to only one dimension in this unfamiliar nonspeech task. [Work supported by NIH Grant No. 2PO1DC00178.]
Wave analysis and synthesis using almost-periodic functions
Authors: Tohyama Mikio , Ushiyama Satoshi , Izuka Masahiro , Hirata Yoshimutsu
Published: October 2005

Spectrum estimation is inevitable for wave analysis and synthesis. Frequency components of a signal are usually estimated by an FFT type of method based on harmonic analysis. This paper demonstrates synthesized waveforms and their spectra analyzed by the nonharmonic method that has been recently proposed by Y. Hirata (to be published in J. Sound Vib.). A conventional FFT-based method generally suffers from severe truncation effects on the spectrum analysis, and consequently a waveform cannot be continuously synthesized in a time region over the observation time interval used for FFT analysis because of virtually assumed periodicity. The nonharmonic method using almost-periodic functions, however, can be applied for the signal analysis and synthesis in a time period over the observation interval. This nonharmonic method is applied not only to stationary waveforms but also to transient signals like room impulse responses. The temporal changes of the frequency components can be visualized without artifacts due to time windowing truncation.
Response of a fluid-loaded shell to excitation as a function of wave number
Authors: Jameson P. W. , Zwillinger D.
Published: October 2005

A procedure has been developed to evaluate the antisymmetric (m=1) response of cylindrical shells under tension which are immersed in convecting fluid. Full wave solutions are used for the fields in the external fluid and also for the elastic materials inside the shell. The shell is modeled as a thin shell using either Kennard’s or Donnel’s shell theory modified by R. Haberman. The internal elastic contents may be a simple fluid or a combination of fluid and interpenetrating solid. In addition there may be an internal coaxial shell. When this system is excited with an external forcing field the displacement response as a function of wave number shows a very complicated dependence on wave number. The physical significance of resonant transverse waves will be discussed and the dispersion of these waves will be related to recent predictions of dispersion by Borgiotti and Rosen; [Borgiotti and Rosen, J. Acoust. Soc. Am. 95, 244–255 (1994)].
A hybrid wave front-resonance analysis of the transient wave response of a fluid-loaded structure
Authors: Lu I-Tai , Yao Yugi
Published: October 2005

Two complementary descriptions can be employed to characterize the transient wave response of a fluid-loaded structure. In the oscillatory description, the wave phenomena are synthesized by global resonances that take the form of damped sinusoidal responses. In the progressing description, the wave phenomena can be organized in terms of wave fronts that travel from the source to the scatterer, and then interact with the scatterer to generate new wave fronts that travel to the sensor. Regarding the computational efficiency, the progressing description is effective to represent the early time arrivals because of time causality, but the oscillatory description is convenient to describe the late arrivals where the medium has fully responded to the excitation. With respect to data acquisition and interpretation, both arrival times of wave fronts and resonant frequencies of oscillatory waves are good physical observables. Therefore, a hybrid combination of these two representations are desirable for applications such as detection and classification. Here, the concept is demonstrated by a systematic formulation and numerical examples. Time-frequency analysis is also employed to interpret the simulation results. [Work supported by ONR and NRL.] a)On sabbatical leave and is visiting Naval Res. Lab., Washington, DC.
Modal approach and statistical energy analysis of plate structures subject to point excitations
Authors: Gibbs B. M. , Moorhouse A. T.
Published: October 2005

A global mode approach to the bending vibration of structures composed of thin rectangular plates is described and applied to a T combination of five plates under point excitation. The boundary conditions at the edges, including the junctions between the plates, allow rotation only but a complex rotational stiffness can be incorporated to model conditions ranging continuously from the simply supported to the rigidly clamped condition at the non coupled edges. Predicted point and transfer mobilities on the same plate and across one or more junctions give good agreement with scale model measurement. The method of analysis can be used in the frequency region of high modal overlap where statistical energy analysis applies and predicted spatial average bending energies, obtained by both methods, compare favorably. Results also compare favorably with scale model measurement. The computational time for the modal approach is not long and a study is proposed involving a parametric survey where SEA terms can be redefined and an estimate made of their sensitivity to variations in frequency, excitation, dimension and material properties.