Showing papers in "Journal of the Acoustical Society of America in 1983"
TL;DR: The value of the auditory-filter bandwidth continues to decrease as center frequency decreases below 500 Hz, and a method is described for calculating excitation patterns from filter shapes.
Abstract: Recent estimates of auditory‐filter shape are used to derive a simple formula relating the equivalent rectangular bandwidth (ERB) of the auditory filter to center frequency. The value of the auditory‐filter bandwidth continues to decrease as center frequency decreases below 500 Hz. A formula is also given relating ERB‐rate to frequency. Finally, a method is described for calculating excitation patterns from filter shapes.
941 citations
Journal Article•
TL;DR: A novel technique that considerably extends the bounds of computational feasibility of the exact test is proposed here and is transformed into one of identifying all paths through a directed acyclic network that equal or exceed a fixed length.
874 citations
TL;DR: An analytic model is described for application in ultrasonic tissue characterization that treats spectra derived from received echo signals and relates them to physical tissue properties and has proven useful in interpreting data from various types of tissues.
Abstract: An analytic model is described for application in ultrasonic tissue characterization. The model is applicable to clinical broadband pulse echo systems. It treats spectra derived from received echo signals and relates them to physical tissue properties. The model can be applied to deterministic tissue structures (e.g., retinal detachments, larger blood vessels, and surface layers of the kidney) and to stochastic tissue structures (e.g., various tumors). The beam patterns included in the model are those generated by focused transducers typically used in high-resolution clinical ultrasound. Appropriate calibration procedures are also treated; these are needed for interpretation of absolute spectral parameters. The results obtained with the analytic model have been used to design a digital processing system and the associated techniques which are now being applied during examinations of the eye and abdominal organs. The results have proven useful in interpreting data from various types of tissues. To illustrate the application of these results, representative clinical data, obtained from the digital system, are presented for two types of tissue architectures. The first case is a detached retina representing a deterministic structure characterized by well-defined thickness and reflection coefficients. The second case is asteroid hyalosis and represents a stochastic entity in which the positions of small scattering particles are best described in statistical terms, and characterization is accompanied by means of normalized power spectra.
637 citations
TL;DR: In this paper, a transducer array is used for sound reproduction of a new type of loudspeaker based on the nonlinear acoustics of sound wave interaction in air, where a finite amplitude ultrasound wave that can be amplitude modulated by any audio signal is radiated from a transducers array into air as the primary wave.
Abstract: This work was done to devise a new type of loudspeaker. The theory for sound reproduction of this loudspeaker is based on nonlinear acoustics of sound wave interaction in air. A finite amplitude ultrasound wave that can be amplitude modulated by any audio signal is radiated from a transducer array into air as the primary wave. As a result, an audio signal is produced in the air because of the self‐demodulation effect of the AM sound wave due to the nonlinearity of the air. It is possible to get a flat characteristic of reproduced sound pressure by using an equalizer. In some fundamental experiments the characteristic of the reproduced sound pressure is not quite flat due to an imperfect transducer array. Improvement of the transducer makes it possible to get a flat characteristic. A special feature of this loudspeaker is its very sharp directivity pattern, which makes it possible to realize a sound spotlight.
371 citations
TL;DR: In this article, the authors describe a model for the nonlinear behavior of the clarinet, violin, and flute families with very little programming effort, and demonstrate that a single set of model equations has relevance to all three families.
Abstract: The time‐domain description of musical and other nonlinear oscillators complements the more commonly used frequency‐domain description, and is advantageous for some purposes. It is especially advantageous when studying large‐amplitude oscillations, for which nonlinearity may be severe. It gives direct insight into the physical reasons for the variation of waveform as playing conditions vary, and into certain phenomena which may seem counter‐intuitive from the frequency‐domain viewpoint, such as the musically undesirable flattening in the pitch of a bowed string when the bow is pressed too hard onto the string. It is easy to set up efficient time‐domain simulations on a small computer, a fact that has been surprisingly little exploited in musical acoustics. The simplest relevant model is described here. It demonstrates some of the basic nonlinear behavior of the clarinet, violin, and flute families with very little programming effort. Remarkably, a single set of model equations has relevance to all three c...
348 citations
TL;DR: In this article, a model was developed that predicts the acoustical characteristics of rigid fibrous absorbents soils and sands from five parameters: porosity, flow resistivity, tortuosity, steady flow shape factor, and dynamic shape factor.
Abstract: A model is developed that predicts the acoustical characteristics of rigid fibrous absorbents soils and sands from five parameters. These parameters are porosity, flow resistivity, tortuosity, steady flow shape factor, and dynamic shape factor. Tortuosity is shown to be related simply to porosity and a simple relationship between the shape factors is postulated. In practice, therefore, only two measurable parameters (porosity and flow resistivity) are required together with a third shape factor parameter, appropriate values of which are deduced for the media of interest by comparison with appropriate measurements. The model is shown to give superior predictions to those of empirical formulae that use flow resistivity only, particularly when applied to high flow resistivity soils and sands at low frequencies such that the stated range of validity of the empirical formulae is exceeded.
340 citations
TL;DR: The free-field speech-reception threshold (SRT) for sentences was investigated in quiet and under nine conditions involving noise or competing speech for a group of 20 elderly subjects and a reference group of ten young normal-hearing subjects, finding that the elderly are unable to make full use of the spatial divergence between primary speaker and noise source.
Abstract: The free-field speech-reception threshold (SRT) for sentences was investigated in quiet and under nine conditions involving noise or competing speech for a group of 20 elderly subjects (ten male, age 75-85; ten female, age 76-88) and a reference group of ten young normal-hearing subjects The noise source had the same long-term average spectrum as the competing speech The interfering signals were presented at a constant level of 55 dBA All elderly subjects had moderate, nearly symmetrical pure-tone hearing losses with an average loss at 500, 1000, and 2000 Hz of between 9 and 40 dB re: ISO-389 The main results are (1) the SRT values in noise and competing speech are about equal, whereas the normal-hearing subjects showed a lower SRT (7 dB lower for the condition that both sound sources are in front) in competing speech than in noise; apparently, the elderly subjects do not benefit from the relatively silent periods in competing speech; (2) the gain obtained by moving the interfering noise source from the front to the lateral position is only 25 dB, in contrast to a gain of 96 dB for the young subjects; apparently, the elderly are unable to make full use of the spatial divergence between primary speaker and noise source
294 citations
TL;DR: In this article, a simple experiment was carried out to demonstrate the phenomenon of Anderson localization in an acoustical context, where the propagation of vibration in a structure which is not entirely regular is impeded by the irregularities, giving rise on the average to an exponential decay of vibration level away from the driving point, even in the absence of any dissipation.
Abstract: This article describes the theory and a simple experiment carried out to demonstrate the phenomenon of Anderson localization in an acoustical context. This is an effect whereby the propagation of vibration in a structure which is not entirely regular is impeded by the irregularities, giving rise on the average to an exponential decay of vibration level away from the driving point, even in the absence of any dissipation. The structure used in the experiment was a stretched string with masses attached to it. This string was studied with regular spacings of the masses and after the masses had been moved in a controlled way to provide a small degree of irregularity. In both cases, the transmission of energy from end to end of the string was measured as a function of frequency, and also the mode shapes in the second and fourth passbands were measured so as to demonstrate the underlying physics of the localization phenomenon, in which the individual modes making up each passband change from being extended throughout the structure in the regular case to being localized in specific areas of the structure in the presence of irregularity. All measurements yielded satisfactory agreement with the theoretical predictions.
241 citations
TL;DR: In this article, the relationship between scattering data obtained from ultrasonic experiments, in which the waves are excited and detected in a finite measurement geometry, and unbounded medium, farfield scattering amplitudes is considered.
Abstract: The relationship between scattering data obtained from ultrasonic experiments, in which the waves are excited and detected in a finite measurement geometry, and unbounded medium, farfield scattering amplitudes is considered. For a scatterer in a single fluid medium, a Green’s function approach is used to develop an approximate, but absolute, relationship between these experimental and theoretical cases. Electromechanical reciprocity relationships are then employed to generalize to a two medium case in which the scatterer is located in an elastic solid which, along with the ultrasonic transducer, is immersed in a fluid medium. The case explicitly considered is one in which the incident waves are quasiplanar over the volume of the flaw and the scattering amplitudes are slowly varying over the range of angles subtended by the receiving transducer. Analytic approximations are developed for the absolute relationship of the received transducer signal to the unbounded medium scattering amplitudes, and formal exp...
237 citations
TL;DR: Experiments summarized herein support the view that the most important source of information for speaker-invariant vowel identity is carried in dynamic specification of vowel onset and offset spectral patterns, with vowel duration also playing a role.
Abstract: This chapter summarizes research conducted over a 35 year period on the dynamic specification of vowels. A series of experiments comparing vowels in consonant context with vowels produced in isolation failed to support talker normalization theories that predicted higher accuracy through prior exposure to a talker’s “point vowels.” Instead, these studies showed that vowels in consonant context were more accurately identified than isolated vowels, supporting a dynamic specification of vowels theory over static target theories, leading to the proposal that important information is contained in the formant transitions. Consonant–vowel coarticulation is not a source of “noise”, rather it gives rise to an acoustic array in which the consonants and vowels are cospecified in the time-varying spectral configuration which we call dynamic specification. Subsequent experiments showed high identification accuracy for “silent center vowels” in which the central portion of the CVC syllable was removed by gating. Identification accuracy was not disrupted when the onset and offset portions were produced by different speakers. Vowel identification improved with increasing duration of the onsets or offset portions. Onsets were identified more accurately than offsets but neither was as well identified as the silent center syllables. Collectively these and other experiments summarized herein support the view that the most important source of information for speaker-invariant vowel identity is carried in dynamic specification of vowel onset and offset spectral patterns, with vowel duration also playing a role. Subsequent experiments with North German vowels, which do not exhibit the degree of vowel diphthongization reported in American English dialects, showed that listeners rely on dynamic spectro-temporal information specified by syllable onsets and offsets, in addition to cues provided by inherent vowel duration. Cross-language comparisons are presented from the perspective of adaptive dispersion theory. These comparisons support the view that dynamic properties are perceptually more important in differentiating vowels in languages with large vowel inventories.
234 citations
TL;DR: The animal data support the notion that second-formant transitions are sufficient to allow the appropriate partitioning of a place continuum in the absence of associative pairing with other more complex cues and discuss two potential roles played by audition in the evolution of the acoustics of language.
Abstract: Discrimination of speech‐sound pairs drawn from a computer‐generated continuum in which syllables varied along the place of articulation phonetic feature (/b, d, g/) was tested with macaques. The acoustic feature that was varied along the two‐formant 15‐step continuum was the starting frequency of the second‐formant transition. Discrimination of stimulus pairs separated by two steps was tested along the entire continuum in a same–different task. Results demonstrated that peaks in the discrimination functions occur for macaques at the ‘‘phonetic boundaries’’ which separate the /b–d/ and /d–g/ categories for human listeners. The data support two conclusions. First, although current theoretical accounts of place perception by human adults suggest that isolated second‐formant transitions are ‘‘secondary’’ cues, learned by association with primary cues, the animal data are more capatible with the notion that second‐formant transitions are sufficient to allow the appropriate partitioning of a place continuum in the absence of associative pairing with other more complex cues. Second, we discuss two potential roles played by audition in the evolution of the acoustics of language. One is that audition provided a set of ‘‘natural psychophysical boundaries,’’ based on rather simple acoustic properties, which guided the selection of the phonetic repertoire but did not solely determine it; the other is that audition provided a set of rules for the formation of ‘‘natural classes’’ of sound and that phonetic units met those criteria. The data provided in this experiment provide support for the former. Experiments that could more clearly differentiate the two hypotheses are described.
TL;DR: In this paper, a coupled mode solution is formulated for the problem of acoustic propagation in a cylindrically symmetric ocean divided, in range, into a finite number of adjoining Pekeris waveguides of differing water depths.
Abstract: A coupled mode solution is formulated for the problem of acoustic propagation in a cylindrically symmetric ocean divided, in range, into a finite number of adjoining Pekeris waveguides of differing water depths. Attenuation is included in the bottom and the problem is discretized by assigning a pressure release boundary condition at a depth which is sufficiently far removed to prevent significant energy from returning to the water. This formulation includes backscatter from the depth variations of the water column and full coupling between a finite number of modes propagating in the water column and in the bottom. Numerical results based on an implementation of this solution are presented.
TL;DR: Running spectral displays derived from linear prediction analysis were used to examine the initial 40 ms of stop-vowel CV syllables for possible acoustic correlates to place of articulation and three proposed time-varying features were shown to be displayed robustly in auditory filtered running spectra.
Abstract: Running spectral displays derived from linear prediction analysis were used to examine the initial 40 ms of stop‐vowel CV syllables for possible acoustic correlates to place of articulation. Known spectral and temporal properties associated with the stop consonant release gesture were used to define a set of three‐time‐varying features observable in the visual displays. Judges identified place of articulation using these proposed features from running spectra of the syllables /b,d,g/ paired with eight vowels produced by three talkers. Average correct identification of place was 88%; identification was better for the male talkers (92%) than the one female talker (78%). Post hoc analyses suggested, however, that simple rules could be incorporated in the feature definitions to account for differences in vocal tract size. The nature of the information contained in linear prediction running spectra was analyzed further to take account of known properties of the peripheral auditory system. The three proposed time‐varying features were shown to be displayed robustly in auditory filtered running spectra. The advantages of describing acoustic correlates for place from the dynamically varying temporal and spectral information in running spectra is dicussed with regard to the static template matching approach advocated recently by Blumstein and Stevens [J. Acoust. Soc. Am. 66, 1001–1017 (1979)].
TL;DR: It turned out that tests on frequency resolution form a cluster, and are approximately independent of audiometric loss, whereas hearing loss for speech in noise is closely allied to frequency resolution, whereas Hearing loss forspeech in quiet is governed by audiometric Loss.
Abstract: Relations between auditory functions, as expressed by coefficients of correlation, were studied for a group of 22 sensorineurally hearing‐impaired subjects with moderate losses. In addition to the audiogram, we measured frequency resolution, temporal resolution, and speech reception in quiet and in noise. Frequency resolution was derived from masking with comb‐filtered noise and from the psychophysical tuning curve, for both paradigms in simultaneous and in nonsimultaneous masking. The critical ratio was also determined. Temporal resolution was determined with intensity‐modulated noise and from backward and forward masking. All tests were performed at 1000 Hz. Correlations among tests were gathered in a matrix and subjected to a principal‐components analysis. It turned out that tests on frequency resolution form a cluster, and are approximately independent of audiometric loss. Furthermore, hearing loss for speech in noise is closely allied to frequency resolution, whereas hearing loss for speech in quiet is governed by audiometric loss.
TL;DR: In this article, a new wide-angle parabolic equation based on operator splitting was proposed for ocean acoustics using a marching-type Fourier transform solution method, which was first presented by Feit and Fleck for studying propagation within optical fibers.
Abstract: In this paper we describe a new wide‐angle parabolic equation based on an operator‐splitting that permits the use of a marching‐type Fourier transform solution method The equation was first presented by Feit and Fleck [Appl Opt 17, 3990–3998 (1978)] for studying propagation within optical fibers Existing computer codes which numerically solve the standard parabolic equation of ocean acoustics by the split‐step algorithm of Tappert and Hardin are easily modified to accommodate the wide‐angle capability of the new equation In addition, since the new wide‐angle equation is less sensitive to the value of the reference wavenumber, the effects of phase errors are greatly reduced The results of a simple error analysis indicate that improved accuracy can be achieved by the new wide‐angle equation for propagation conditions typical of deep ocean environments This is supported by our numerical experience, a summary of which is presented in the paper For test cases, where the variation of the acoustic index
TL;DR: The magnitudes of volume increments during the voiced stops, and the means by which those increments were achieved, differed considerably across place of articulation and phonetic environment.
Abstract: Measurements were made of saggital plane movements of the larynx, soft palate, and portions of the tongue, from a high-speed cinefluorographic film of utterances produced by one adult male speaker of American English. These measures were then used to approximate the temporal variations in supraglottal cavity volume during the closures of voiced and voiceless stop consonants. All data were subsequently related to a synchronous acoustic recording of the utterances. Instances of /p,t,k/ were always accompanied by silent closures, and sometimes accompanied by decreases in supraglottal volume. In contrast, instances of /b,d,g/ were always accompanied both by significant intervals of vocal fold vibration during closure, and relatively large increases in supraglottal volume. However, the magnitudes of volume increments during the voiced stops, and the means by which those increments were achieved, differed considerably across place of articulation and phonetic environment. These results are discussed in the context of a well-known model of the breath-stream control mechanism, and their relevance for a general theory of speech motor control is considered.
TL;DR: At frequencies up to about 1.0 kHz, the variation of gap threshold with frequency matches well the reciprocal of the bandwidth of the auditory filter, as determined from masking experiments using a notched-noise masker, suggesting that the temporal response of the audible filter may limit gap detection at low frequencies.
Abstract: The threshold for detection of a temporal gap in a noiseband was measured. A notched noise masker was used to restrict listening to a limited spectral region. Threshold was measured as a function of center frequency, bandwidth, and level. For a signal bandwidth of one‐half the center frequency, the gap threshold decreased from 22.5 ms for a center frequency of 0.2 kHz to 3.2 ms at 8.0 kHz: a wideband condition provided an estimate of 2.3 ms, a value in agreement with previously published estimates. Bandwidth manipulation showed that the variation with frequency was not due to changes in absolute bandwidth alone. The effect of changes in level was determined at three frequencies, 0.4, 1.0, and 6.5 kHz, using a signal bandwidth of half the center frequency. At all frequencies gap threshold decreased as the signal spectrum level was raised from 10 to 25 dB, but a further increase to 40 dB showed no additional improvement. At frequencies up to about 1.0 kHz, the variation of gap threshold with frequency matches well the reciprocal of the bandwidth of the auditory filter, as determined from masking experiments using a notched‐noise masker. This suggests that the temporal response of the auditory filter may limit gap detection at low frequencies.
TL;DR: In this paper, it was shown that Chessell's single-parameter theory can be used to predict the measured transmission spectra between a source and receiver located above ground surfaces having a wide range of acoustic impedance.
Abstract: Following earlier work by Chessell [J. Acoust. Soc. Am. 62, 825–834 (1977)] it is shown that his single‐parameter theory can be used to predict the measured transmission spectra between a source and receiver located above ground surfaces having a wide range of acoustic impedance—or effective flow resistivity. Surfaces behaving essentially as locally reacting range from new‐fallen snow, effective flow resistivity σ=10–30 cgs rayls, through grass‐covered ground, σ=150–300 rayls, to mature asphalt, σ=30 000 rayls. The thermal‐conduction and viscous boundary layer of the surface limits the effective flow resistivity of even the hardest and most impervious surface to the range 105–106 rayls, depending on frequency: this value is appropriate to evaluate the complex reflection coefficient of the paint‐sealed surface of a thick slab of reinforced concrete.
TL;DR: In this article, a radio transmitter and receiver device with a head band has a transmitting microphone at one end and a receiving speaker at the other end, where one ear is blocked by the speaker but the other ear is open, and therefore, a user can catch noises thereabout.
Abstract: A radio transmitter and receiver device in which a head band has a transmitting microphone at one end and a receiving speaker at the other end. This microphone comprises a bone transmission type microphone for detecting aural oscillation of an external auditory canal transmitted through a bone tissue of a head portion from a mouth, said microphone being brought into contact with a side head portion at the rear of an ear. Thus, one ear is blocked by the speaker but the other ear is open, and therefore, a user can catch noises thereabout. A transmitting and receiving antenna has matching means and is mounted on the side of the speaker.
TL;DR: In this article, a vibratory signal sweep is produced by a vibrating apparatus in accordance with a power spectrum function S(f), which is proportional to a noise component function n(f) and a subsurface signal amplitude attenuation function B(f).
Abstract: Disclosed are a method and apparatus for vibratory seismic prospecting in which a vibratory signal sweep is produced by a vibrating apparatus in accordance with a power spectrum function S(f), which is proportional to a noise component function n(f) and a subsurface signal amplitude attenuation function B(f) for an area to be surveyed, to thereby produce reflection signals having an improved signal-to-noise ratio.
TL;DR: Detailed analysis demonstrates that efficient probabilistic processing of the central spectrum described known psychophysical properties of frequency measurement in discrimination and periodicity pitch experiments.
Abstract: A probabilistic psychophysical model for monaural communication from the auditory nerve to the brain is given in the form of a tonotopic display of stimulus spectrum, termed central spectrum. The model builds upon prior research demonstrating the potential of neural timing cues from the auditory nerve for conveying information on complex spectra, and was designed to meet the quantified demands of the psychophysics of frequency measurement. The central spectrum magnitude at each frequency is determined by the response of the auditory‐nerve fiber with characteristic frequency matching that frequency. An interval histogram from each fiber is passed through a filter matched to the characteristic frequency of the fiber. This output versus characteristic frequency defines the central spectrum. Detailed analysis demonstrates that efficient probabilistic processing of the central spectrum describes known psychophysical properties of frequency measurement in discrimination and periodicity pitch experiments. Psycho...
TL;DR: In this article, the properties of a heat engine that is intrinsically irreversible in the sense that it requires thermal lags for its operation are analyzed quantitatively using a second-order thermoacoustic theory based on the work of Rott.
Abstract: Certain thermoacoustic effects are described which form the basis for a heat engine that is intrinsically irreversible in the sense that it requires thermal lags for its operation. After discussing several acoustical heating and cooling effects, including the behavior of a new structure called a ‘‘thermoacoustic couple,’’ we discuss structures that can be placed in acoustically resonant tubes to produce both substantial heat pumping effects and, for restricted heat inputs, large temperature differences. The results are analyzed quantitatively using a second‐order thermoacoustic theory based on the work of Rott. The qualities of the acoustic engine are generalized to describe a class of intrinsically irreversible heat engines of which the present acoustic engine is a special case. Finally the results of analysis of several idealized intrinsically irreversible engines are presented. These suggest that the efficiency of such engines may be determined primarily by geometry or configuration rather than by temperature.
TL;DR: Determinations of shear wave speeds of sound and attenuation coefficients are reported for soft tissues, a silicone rubber reference material, and a gel used in manufacturing ultrasonically tissue-mimicking materials to allow frequency dependencies to be proposed.
Abstract: Determinations of shear wave speeds of sound and attenuation coefficients are reported for soft tissues, a silicone rubber reference material, and a gel used in manufacturing ultrasonically tissue‐mimicking materials. Fresh bovine tissues were investigated, including calfskin, liver, cardiac muscle, and striated muscle. Because of the very large shear wave attenuation coefficients, reasonably accurate determinations of shear wave properties are difficult to make. The quantity measured directly was the complex reflection coefficient for shear waves at a planar interface between the sample and fused silica. Measurements were made at frequencies spanning the range 2–14 MHz. The shear wave attenuation coefficients increase with frequency and are of the order of 104 times the longitudinal wave attenuation coefficients. The shear wave speeds of sound also increase with frequency but are only a few percent of the longitudinal wave speeds of sound. The results are accurate enough to allow frequency dependencies to be proposed.
TL;DR: In this article, an experiment to verify the basic linearity of fisheries acoustics is described, where Herring (Clupea harengus L.) was the subject fish and acoustic measurements consisted of the echo energy from aggregations of encaged but otherwise free swimming fish.
Abstract: An experiment to verify the basic linearity of fisheries acoustics is described. Herring (Clupea harengus L.) was the subject fish. Acoustic measurements consisted of the echo energy from aggregations of encaged but otherwise free‐swimming fish, and the target strength functions of similar, anesthetized specimens. Periodic photographic observation of the encaged fish allowed characterization of their behavior through associated spatial and orientation distributions. The fish biology and hydrography were also measured. Computations of the echo energy from encaged aggregations, derived by exercising the linear theory with the target strength functions of anesthetized fish and gross behavioral characteristics of encaged fish, agreed well with observation. This success was obtained for each of four independent echo sounders operating at frequencies from 38 to 120 kHz and at power levels from 35 W to nearly 1 kW. In addition to demonstrating the basic linearity of fisheries acoustics, the experiment verified b...
TL;DR: Together, PGG and EGG may provide much of the information obtained from high-speed filming as well as potentially detect horizontal phase differences during opening and closing.
Abstract: This study was designed to compare information on laryngeal vibrations obtained by high‐speed filming, photoglottography (PGG), and electroglottography (EGG). Simultaneous glottographic signals and high‐speed films were obtained from two subjects producing steady phonation. Measurements of glottal width were made at three points along the glottis in the anterior–posterior dimension and aligned with the other records. Results indicate that PGG and film measurements give essentially the same information for peak glottal opening and glottal closure. The EGG signal appears to reliably indicate vocal‐fold contact. Together, PGG and EGG may provide much of the information obtained from high‐speed filming as well as potentially detect horizontal phase differences during opening and closing.
TL;DR: Results provide little support for the claim that sensitivity to the global properties of the onset spectrum underlie place of articulation perception or for Stevens and Blumstein's primary versus secondary cue distinction, but are consistent with the view that dynamic, time-varying information is important in the perception of place of articulatedulation.
Abstract: Stevens and Blumstein [Perspectives on the Study of Speech (Erlbaum, Hillsdale, NJ, 1981)] have proposed that the global shape of the CV syllable onset spectrum provides the listener with a primary and contextually invariant cue for place of stop consonant articulation. Contextually variable formant transitions are, in contrast, claimed to constitute secondary cues to place of articulation that, during development, are learned through their co‐occurrence with the primary spectral ones. In the two experiments reported here, these claims about the relative importance of the onset spectrum and formant transition information were assessed by obtaining adults’ and young children’s identifications of synthetic stimuli in which these two potential cues specified different places of articulation. In general, the responses of both adults and children appeared to be determined by the formant transitions of the stimuli. These results provide little support for the claim that sensitivity to the global properties of t...
TL;DR: In this paper, an artificial pitch contour to phonological linguistic phoneme unit string data is presented. But the pitch contours are not used to improve the spoken intonation contour in low data rate speech applications.
Abstract: The present invention provides an artificial pitch contour to phonological linguistic phoneme unit string data. In the event that the phonological linguistic string data includes some information on intonation contour, such as primary accent, secondary accents and rising or falling intonation mode data, this data is employed along with a determination of syllable type for each syllable to assign one of a predetermined plurality of pitch patterns to each syllable. If such intonation data is not available, as for example in a bar code or text-to-speech system, then primary and secondary accent data are generated based upon the presence or absence of strong vowels involved in word stress syllables. This invention is most useful in improving the spoken intonation contour in low data rate speech applications in which some intonation data is available.
TL;DR: In this paper, a portable vibration monitoring device (10) for use in connection with a base computer (11) which stores data regarding the nature and parameters of vibration measurements to be made on preselected machines for predictive maintenance purposes.
Abstract: A portable vibration monitoring device (10) for use in connection with a base computer (11) which stores data regarding the nature and parameters of vibration measurements to be made on preselected machines for predictive maintenance purposes. The device includes a power module (36) which energizes the various components. A vibration sensor (14) produces an analog signal which is representative of selected vibration parameters. The signal generated by the vibration monitor is conditioned by a signal conditioning module (16) which includes anti-aliasing filters which enhance the accuracy of the data collected. A multiple function module (18) includes various selectively energized modules which enhance the speed and reliability of the data collected. This data is analyzed by a microprocessor and displayed as desired.
TL;DR: In this article, a new approach to direct and inverse scattering problems in the time domain is proposed, which is applied here to the case of a one-dimensional lossless medium, based on an integro-differential equation which is satisfied by the reflection kernel.
Abstract: This paper examines the implementation of a new approach to direct and inverse scattering problems in the time domain, which is applied here to the case of a one‐dimensional lossless medium. The method is based on an integro‐differential equation which is satisfied by the reflection kernel and has been derived elsewhere using invariant imbedding techniques. An example of an exact solution to this equation is given. Numerical schemes for solving the direct and inverse problems are derived by discretizing this equation. The behavior of the resulting algorithms is then tested on several examples. The results suggest that the inversion method is stable in the presence of additive noise.
TL;DR: In this paper, the authors used Biot's theory to search numerically for the velocities of the various surface waves, both the true slow surface wave and the pseudosurface waves, at an interface between a fluid halfspace and a half-space of a fluid-saturated porous medium.
Abstract: We use Biot’s theory to search numerically for the velocities of the various surface waves, both the true slow surface wave and the pseudosurface waves, at an interface between a fluid half‐space and a half‐space of a fluid‐saturated porous medium. We focus on the high‐frequency range where the Biot–Plona slow wave is propagatory. We find that for an open‐pore surface situation, the true surface mode exists for a limited range of material parameters and changes continuously into a slightly leaky pseudo‐Stoneley mode as the mode speed increases past the slowest bulk wave speed; for the sealed pore situation there exist simultaneously a true surface mode (for all values of material parameters) and a pseudo‐Stoneley mode. The pseudo‐Rayleigh mode has features similar to those of the pseudo‐Rayleigh mode for a fluid/nonporous solid case.