bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual recognition of words from palatometric displays
Authors: Fletcher Samuel G.
Published: October 2005

The relation between visually perceived palatometric patterns and word recognition was measured using palatometric representations from 16 words shown on a video monitor. Five subjects examined the patterns and identified the words spoken. Words identified at 90% or higher accuracy rate were classified as “recognized.” Virtually immediate recognition of some words and rapid development of recognition for all of the words were found. Few errors were observed in the responses of any subject after the 6th of 10 experimental days. Analysis of the data indicated that word length, consonant manner of articulation, consonant and vowel place of articulation, and movement timing were the visual attributes used to differentiate the palatometric displays. An articulatory feature analysis indicated that the visually perceived attributes of the displays parallel those found in acoustic studies. The findings suggest that phonetic features may not be sensory avenue dependent. The findings will be interpreted with respect to modeling and shaping speech of the deaf. [Work supported by the NINCDS.]
The Indiana speech training aid (ISTRA)
Authors: Kewley-Port Diane , Watson Charles S. , Elbert Mary
Published: October 2005

The ISTRA system is being developed to improve the speech of deaf or misarticulating children. The system consists of a microcomputer equipped with a low-cost, speaker-dependent speech recognizer. One-line feedback concerning the quality of entire utterance is derived from the degree of match between a stored template and the new utterance. Software for conducting speech training (under the guidance of a speech pathologist) has been developed over 3 years based on the collaboration of research scientists, clinicians, and programmers. Clients are able to run their speech drills independently using a variety of drills in game formats. Ongoing clinical evaluation of ISTRA training has employed single-subject design experiments. In these studies, “blind” listener juries rated the speech of words collected before, during, and after training. Results show significant improvement of the quality of words trained in the ISTRA drill, as well as generalization to nontrained words. One ISTRA system has been used for regular speech training in an elementary school with positive results, both for improved speech as well as enthusiastic acceptance of the device. A description of the results of 3 years of research with ISTRA will be presented. [Research supported by NSF.]
Speech visualization and its application for the hearing impaired
Authors: Watanabe Akira , Ueda Yuichi
Published: October 2005

A speech-visualization system has been developed as an extension of research on a color display system for connected speech [Watanabe et al., IEEE Trans. Acoust. Speech Signal Process. ASSP-33, 164–173 (1985)]. In this newly developed system, normalized spectrographic patterns are overlapped as a change of luminance on a whole pattern that represents voiced segments by colors. The spectrographic patterns are represented with high luminance in unvoiced portions, and with low luminance in voiced ones so as not to disturb the color image. This extension allows unvoiced plosives as well as fricatives and affricates to be clearly visualized by the sharp contrast between their black-and-white patterns and the vivid colors of the voiced components. Moreover, in order to generate a visually clear image, a cleaner, which eliminates unnecessary patterns such as aspirates that are often observed at the end of utterances, is introduced. Finally, two applications of this system are described. One is a speech training system in which a personal computer, with a database, controls the speech-visualization system and provides a hearing aid. The other is a telecommunication system that utilizes a public telephone channel. [This work was supported by TAF.]
A new speech training system for profoundly deaf children
Authors: Yamada Yoshinori , Murata Norio , Oka Tatsuo
Published: October 2005

A new speech training system based on a personal computer has been developed. Monitoring of the articulatory movements and speech sounds of individuals was accomplished using five sensors: a microphone, a neck sensor for vocal cord vibration, a nose sensor for nasal sound, an expiratory airflow sensor, and a tongue position sensor. Signals from these sensors were processed in real time by a DSP to extract ten training parameters that are useful for prosodic or phonemic training. These parameters were transferred to an MSX personal computer every 10 ms and were displayed on a color CRT screen together with a training model in front of which the trainee repeatedly practices his speech. Such training was conducted for profoundly deaf children (aged 4–6) for 2 years at the School for the Deaf, University of Tsukuba, and has been enthusiastically accepted and used. After 2 years of this training, remarkable improvements in the intelligibility of monosyllables were attained that had not been attained by conventional methods.
Linguistic processing in aids for the handicapped
Authors: Hunnicutt Sheri
Published: October 2005

Since 1971, various linguistic components have been developed for text-to-speech systems that are used as aids for disabled persons, for symbol-to-speech systems for nonspeaking individuals, and for word prediction for motorically disabled persons. The text-to-speech systems, or later versions of them, are used as speech prostheses for nonvocal persons and as computer display readers for blind computer users. The symbol-to-speech system is an expanded version of one of the text-to-speech systems [Carlson et al., Proc. ICASSP (1982)]. To convert symbols to phoneme strings, both lexicons and parsers were developed for four languages. In two languages, symbol-to-text systems were also developed. These systems are used as communication aids by persons experiencing severe speech and motor disabilities. Several algorithms have been designed to predict words from partial information. One program is being used as a speaking or writing aid. A second program is being tested as an aid in aphasia rehabilitation. It is planned that the third algorithm will be used by speaking persons in need of written output capability in conjunction with a speech recognition system.
An integrated voice analysis system for clinical use
Authors: Kasuya Hideki , Kikuchi Yoshinobu
Published: October 2005

The need for acoustic methods for the quantitative evaluation of voice quality arises in many voice research and clinical areas. Since the voice quality is associated with multidimensional physical characteristics of a voice signal, the acoustic evaluation must be made on the basis of various acoustic measurements from the signal. An integrated voice analysis system has been developed, primarily aiming at applications for the quantitative evaluation in voice clinics. The system uses the ARIEL DSP-16 and an IBM-PC/AT computer. The acoustic measurements made by the system include: the average pitch frequency, jitter, shimmer, vocal noise, gross spectral shape, formant frequencies and levels, temporal variations in the frequency spectrum, and so on. The key features of the system and several examples of its clinical application will be presented.
Design of an intelligent artificial larynx
Authors: Hiki Shizuo , Kakita Yuki
Published: October 2005

The artificial larynx proposed in this paper can control the following features automatically: (a) voicing onset/cessation, (b) a brief stop in vibration for voiceless consonants, (c) variation in fundamental frequency, and (d) intensity for prosodic information. This device consists of three parts: (1) a detector of biological signals, i.e., sound, electromyograms (surface), air pressure and airflow, tactile information on the skin surface surrounding the larynx, etc.; (2) the controller for sound source, in which control parameters are derived from the biological signals; and (3) a sound source, which is to be implanted in the neck. To investigate the basic characteristics of the timing factors, (a) and (b) mentioned above, a manual operation scheme was examined by employing specially designed switches. The timing control is to be replaced by the remaining functions of the speech muscles. Also, a result of the experiment on the control of prosodic information, (c) and (d) above, using airflow, is presented. [Work supported by Grant-in-Aid for Scientific Research, The Ministry of Education, Science and Culture, Japan.]
Predicting aided speechreading performance in segment identification tasks
Authors: Braida Louis D.
Published: October 2005

Auditory presentation of low-frequency speech components, and tactile or electrocochlear stimulation derived from speech, can improve the speechreading of speech segments. A method is described for predicting both the level of aided performance and the resulting error pattern from the confusion matrix for each modality separately. The method is based on a characterization of confusion matrices in terms of a multidimensional Thurstonian decision model that allows performance to be described in terms of sensitivity and bias. In the multimodal case, the decision space is assumed to be the product space of the decision spaces corresponding to the stimulation modes. In certain cases, multimodal sensitivity is roughly equal to the vector sum of the sensitivities for each stimulation mode, indicating that cues are integrated with little interference. [Work supported by NIH.]
Comparison of three sentence-level tests for evaluating audiovisual performance of subjects using a cochlear implant
Authors: Rabinowitz W. M. , Grant Ken W. , Eddington D. K.
Published: October 2005

Postlingually deafened adults implanted with the Symbion cochlear prosthesis have been tested for audiovisual reception of isolated sentences. Three different sets of sentence materials have been used: (a) CID everyday sentences, including live and recorded versions; (b) CUNY sentences developed by Boothroyal et al. (CUNY Rep. RCI10), presented from videodisc; and (c) IEEE/Harvard sentences, from in-house recordings. The tests were conducted in three modes: vision (speechreading) alone, sound alone, and sound plus vision. No feedback was given and, except for the live-voice CID tests, sentences were never repeated for a given subject. Results indicate that all three materials are sensitive to detecting whether the cochlear implant provides a benefit to speechreading, but the CID and CUNY sentences frequently exhibit ceiling effects that limit their ability to differentiate the degree of benefit. The more challenging IEEE/Harvard sentences have reduced ceiling effects and provide other useful performance measures. Specifically, the benefit to speechreading provided by the prosthesis at speech-to-noise ratios of 0–3 dB is roughly one-half that provided in quiet. [Work supported by NIH.]
Quasiarticulatory tactile syllables in a long-term training experiment
Authors: Tillmann H. G. , Piroth H. G.
Published: October 2005

Tactile syllable equivalents were constructed that map relevant articulatory gestures onto the left forearm in a quasi-isomorphic way [cf. H. G. Piroth, J. Acoust. Soc. Am. Suppl. 1 79, S73 (1986)]. The patterns were delivered by the 16-channel “system for electrocutaneous stimulation SEHR-2” [H. G. Tillmann and H. G. Piroth, J. Acoust. Soc. Am. Suppl. 1 79, S73–574 (1986)]. The present investigation was designed to determine whether a subject is able to acquire extensive inventories of tactile patterns. One subject had to train tactile obstruent-vowel syllables with a fixed vowel. During each test run, a subset of the set of tactile obstruents followed by /ɑ:/ was presented repeatedly in a systematic order. Then, the same subset was trained in an identification test with a feedback after each stimulus. When the average recognition rate yielded 80%, the subset was enlarged. After 35 test runs, the subject could identify 12 obstruent patterns (/p,t,k,b,d,g,f,∫,x,v,ȝ,v̥/) at criterion levels. Training the complete set of 16 patterns (/s,z,ç,j/added), he just failed to reach the criterion after 39 additional test runs (75.8%).
Speech enhancement for the hearing impaired by envelope filtering on a loudness scale
Authors: Kollmeier Birger , Hohmann Volker
Published: October 2005

Dynamic compression systems for sensorineural hearing-impaired subjects reduce intensity fluctuations, although they are an important cue for understanding speech. To overcome this effect, an envelope high-pass filter operating in the loudness domain is evaluated, which even enhances these intensity modulations: The output of a filterbank is low-pass filtered to extract the envelope of incoming speech. Loudness scaling data from normal listeners and from each individual impaired listener is used to convert the envelope to a loudness scale value and to convert the high-pass-filtered loudness back to the “desired” envelope value, respectively. The output signal is finally obtained by summing up the filterbank channels after correcting their amplitude. Loudness scaling and intensity modulation discrimination data of several sensorineural hearing-impaired subjects will be presented, as well as speech intelligibility scores for a German CVC rhyme test with and without the algorithm. First results indicate that even no loudness filtering improves speech intelligibility in a wide range of input levels. However, the effect of high-pass filtering in the loudness domain is only moderate. [Work supported by Deutsche Forschungsgemeinschaft.]
Automatic speech recognition for speech-impaired people
Authors: Carlson Gloria Stevens , Bernstein Jared , Bell Donald W.
Published: October 2005

SRI has been evaluating automatic speech recognition for text input by speech-impaired people. The speech of 85 speech-impaired people (primarily deaf and cerebral palsy) was recorded. This speech was input to a high-performance, template-based speech recognizer. With a 300-word vocabulary, the machine recognized approximately 25% of the impaired speakers better than human listeners did (in context); with a 50-word vocabulary, the machine recognized approximately 57% better than listeners. A preprototype text-entry and communication aid is being evaluated in our laboratory. Twelve subjects have tried this system briefly, four of whom could use speech input faster than typing input after only a few minutes of practice. Two subjects (who were not immediately faster with speech input) were trained and evaluated on the system more extensively. Both subjects' performance with the speech recognizer improved dramatically; after 9 h of practice, one's speaking rate almost doubled his manual typing rate. This presentation will describe this system, discuss our results, and show videotapes of the two trained users. [Work supported by NIH.]
Sensory integration of speech by a profoundly deaf subject using tactile aids
Authors: Lynch Michael P. , Eilers Rebecca E. , Kimbrough Oller D. , Pero Patricia J.
Published: October 2005

Previous research on tactual speech perception has focused on the relative contributions of lipreading and taction with normally hearing subjects. The integration of information from touch with that from lipreading and aided hearing by profoundly deaf subjects has not been investigated. In the present study, a profoundly deaf adult with previous tactual vocoder training [Lynch et al., J. Acoust. Soc. Am. Suppl. 1 82, S22 (1987)] was unable to identify a group of words in any one of three conditions, lipreading (L), aided hearing (H), or touch. The tactile devices used were a multichannel electrocutaneous vocoder (TV) and a two-channel vibrotactile aid (TA). To test sensory integration, the words were randomly assigned to one of seven conditions: (a) L + H, (b) H + TV, (c) H + TA, (d) L + TV, (e) L + TA, (f) L + TV + H, and (g) L + TA + H. Results indicate that: the subject integrated information across all three modalities, yielding highest performance in the L + TV + H and L + TA + H conditions; integration occurred when both lipreading and touch were used; integration occurred when both lipreading and aided hearing were used; and each of the tactile devices provided substantial speech information. Analyses of the subject's error patterns and sentence identification performance will also be presented. [Work supported by NIDRR, Dade County Public Schools, and NIH.]
Effects of number of channels on speech perception with tactile aids
Authors: Weisenberger Janet M.
Published: October 2005

Although there is considerable evidence that multichannel tactile aids for the hearing impaired provide more information about the speech signal to the wearer than do single-channel tactile aids, it has not been determined how many channels are necessary for optimal transmission of speech information. In the present study, the 5-channel Tactaid V (Audiological Engineering Corporation) and the 16-channel Queen's University tactile vocoder were evaluated in a series of phoneme identification and connected speech tasks, to determine whether the additional channels present in the 16-channel design lead to better speech perception performance. Results showed that, in relatively simple tasks, such as minimal pairs phoneme discrimination, subjects performed at similar levels with both devices. However, in more complex tasks, such as integration with lipreading, the 16-channel device yielded significantly higher levels of performance. In connected discourse tracking, both devices showed significantly higher levels of performance in conjunction with lipreading than were found under lipreading alone conditions. Results are discussed with respect to the benefits provided by a tactile aid relative to the practical limitations of tactile aids that employ a large number of tactile transducers. [Work supported by NIH and NSF.]
Development of speech perception and speech production of children who used vibrotactile aids
Authors: Proctor Adele , Goldstein Moise H.
Published: October 2005

Since 1977, an extensive video and audio tape database on the use of single-channel vibrotactile aids by prelingually deaf children has been developed. Subjects' ages ranged from 6 weeks to 5 years at the beginning of vibrotactile aid usage. To date, subjects have been followed from periods ranging from 4 to 12 years old. Formal and standardized tests of language, lipreading, speech perception, and speech production were administered as a means of assessing children's progress. Results suggest that aid usage encourages vocalization and facilitates awareness of environmental and speech sounds, learning of lipreading, and acquisition of reading and other aspects of language. Samples of video recordings that demonstrate speech perception and speech production will be shown. [Work supported by DOE, Grant No. 133 GH70189, Department of Health and Human Services Grant No. RR07143, National Foundation March of Dimes.]
Active vibration control of flexural power flow in beams
Authors: Fuller Chris R. , Gonidou Luc O.
Published: October 2005

Active control of flexural power flow in infinite and semi-infinite thin elastic beams by point force inputs is analytically studied. Various forms of terminating impedances or discontinuities positioned on the beam are also considered. The influence of system parameters such as the discontinuity impedance and effects such as bending nearfield generation on the location and number of control actuators and error sensors is investigated and discussed. The mechanisms by which control is achieved are considered. It is demonstrated that these types of boundary conditions strongly influence the choice of optimal controller format. For example, if the error signal only contains information from the propagating wave component, then only one control actuator is needed for complete attenuation of flexural power flow. Finally, preliminary results of a companion experimental investigation will be discussed and compared with the theoretical developments. [Work supported by NASA Langley Research Center.]
Active acoustic absorber for plane waves in water
Authors: Bao X.-Q. , Varadan Vijay K. , Varadan Vasundara V.
Published: October 2005

Presented here is the design of an active acoustic absorber that absorbs normally incident plane waves and completely eliminates reflection. The absorber consists of incoming and reflected wave sensors, an absorption transducer, and an associated control system. The signal due to the incoming wave is sensed, then amplified, using an amplifier with an appropriate transfer function, and then used to actuate the absorption transducer. The error of elimination is detected by the reflected wave sensor, with the control system making the error approach a zero value. Data from experiments conducted in an acoustic pulse tube are also presented. [Work supported by the Research Center for the Engineering of Electronic and Acoustic Materials.]
Modeling and vibration control of multi-link flexible arms
Authors: Ishii Shinya , Yasuda Chiaki , Fujita Katsuhisa
Published: October 2005

Linear state-space models describing the motions of single-link and two-link flexible manipulators are derived by an assumed mode method. These motions are assumed to be a linear combination of a vibration due to flexible deflections and a rigid-body motion. By assuming the flexible arms to be Bernoulli-Euler beams, their vibration behaviors are described by using the partial differential equations with well-posed boundary conditions, which constitute eigenvalue problems. These problems can be solved either by the symbolic processing system or by the finite element method. The controller is designed by the optimal regulator control theory using the quadratic cost function. The stress at the link's root, the angular displacement of the hub, and the angular velocity of the motor are adopted as the feedback signals. The experimental systems of these single-link and two-link models are assumed to have planar motions, and the relative motions of the two links are assumed to result from torques applied at each joint of the systems. Also, the second joint and end effector are assumed to be supported by air bearings on a flat table so as to eliminate the effects of gravity. The experimental results will be presented. The method described above can also be applied to multi-link systems.
On synthetic aperture sonar
Authors: Shishido Masaaki
Published: October 2005

Synthetic aperture technology is used in airborne radar or on satellites like SEASAT to obtain high-resolution pictures of the Earth's surface. On the other hand, in the field of underwater acoustics, the effectiveness of synthetic aperture side-looking sonar has long been predicted. However, this has not come to practical use, mainly because of the influence of the trembling motion of the sonar platforms. First, the principle of synthetic aperture sonar and the similarity between CDP stacking of seismic exploration and synthetic aperture processing are discussed. Then, the influence of platform trembling on the synthetic aperture beamforming is quantitatively studied, and the degradation of the picture is evaluated with computer simulation to show the allowable range for the trembling motion amplitude and period against the used signal frequency.
The time-domain parabolic wave equation and its path integral representation
Authors: Dacol Dalcio K.
Published: October 2005

A path integral representation for the solution of a time-domain parabolic wave equation (TDPE) was developed. It shows promise for describing propagation of sound pulses in the ocean when boundary interactions can be neglected. The TDPE is a linearized version of McDonald and Kuperman's nonlinear progressive wave equation [B. E. McDonald and W. A. Kuperman, J. Acoust. Soc. Am. 81, 1406 (1987)]. Using the techniques developed by these authors one can derive the TDPE from the acoustic wave equation thus showing that the TDPE's solution is an approximate solution to the acoustic wave equation [M.D. Collins, J. Acoust. Soc. Am. Suppl. 82, S122 (1987)]. The TDPE has the mathematical structure of a time-dependent Schrödinger equation and a phase space path integral representation for its solution can be constructed by well-known methods. Applications to be discussed include propagation in a sound channel and in randomly fluctuating media. [Work supported by U.S. Naval Research Laboratory.]
Numerical modeling of acoustic emission from propagating cracks in an Arctic ice cover
Authors: Schmidt Henrik , Kim Jae Soo
Published: October 2005

An earlier developed numerical model for three-dimensional propagation in horizontally stratified fluid/elastic media [H. Schmidt and J. Glattetre, J. Acoust. Soc. Am. 78, 2105–2114 (1985)] has been modified to incorporate seismic moment representations for compact cracks of tensile, dip-slip, and strike-slip types. The applied global matrix approach first yields the depth-dependent Green's function simultaneously in all layers for an arbitrary number of individual source depths. The frequency domain solution for a three-dimensionally propagating crack is then determined by wavenumber integration over a spatial grid of superpositions of individual source contributions multiplied by the proper phase terms. Finally, the time domain solution over the spatial grid is obtained by simple Fourier synthesis. The present Fourier transform approach has the advantage that many crack propagation scenarios can be treated with only a single computer intensive solution of the wave equation. Once the depth-dependent Green's function has been determined for the relevant crack type and depths, the field can be evaluated very efficiently by superposition for any crack propagation direction and speed. The developed model has been applied to theoretical analysis of the sound field produced in an Arctic environment by ice cracking, demonstrating the effect of cracking mechanisms, propagation speed as well as environmental parameters in general. [Work supported by ONR.]
Effects of scalae tapering, perilymph viscosity, helicotrema, and the cochlear map function (CMF) on models of the cochlea
Authors: Puria Sunil , Allen Jont B.
Published: October 2005

The basilar membrane response was calculated by cascading two-port ABCD matrices that are formulated to include effects due to scalae tapering, perilymph viscosity, and helicotrema. Previously, Koshigoe et al. Acoust. Soc. Am. 74, 456–492 (1983)] showed that perilymph viscosity has an important effect on cochlear input impedance (Zc) in the frequency region below 500 Hz. It is shown that Zc is affected more by scala tapering than by perilymph viscosity, and it is affected very little by the helicotrema. It is also shown that low-frequency standing wave (LFSW)'s seen in Zc of several models [J. W. Mathews, Ph.D. thesis, Washington University, Missouri (1980)] are strongly dependent on the CMF used. LFSW's present in nonlinear time domain solutions are likely to manifest themselves across the entire frequency spectrum and as a result mislead one's conclusions regarding basilar membrane mechanics. Previous models have used a straight CMF of the form K0 exp (− ax) resulting in LFSW's. Liberman's CMF leads to a reduction of LFSW's and when Greenwood's drooped CMF [J. Acoust. Soc. Am. 33, 1344–1356 (1961)] is used LFSW's are not present.
Organization of ferret auditory cortex
Authors: Fleshman James W. , Shamma Shihab A.
Published: October 2005

Tone-responsive neurons were studied in the temporal cortex of pentobarbital-anesthetized ferrets. In agreement with Kelly et al. [Hear. Res. 24, 111–115 (1986)], we found a region contained within the curve of the suprasylvian sulcus (SSS) in which low frequencies were represented ventrolaterally and high frequencies dorsomedially. This area, provisionally identified as AI, contains cells that are narrowly tuned and respond at short latency (15–25 ms) to tones. AI is almost completely surrounded by a belt of tone-responsive cortex with differing properties. Rostral to AI, near the anterior limb of the SSS, two regions were identified, both vigorously responsive to tones, with minimum latencies comparable to those in AI: one was characterized by broad tuning; the other displayed tonotopically ordered, primarylike tuning, perhaps corresponding to area A in the cat. Two other regions were characterized by rapidly adapting, broadly tuned responses with relatively long latencies (30–150 ms). A caudal strip extends into the posterior limb of the SSS and may exhibit a tonotopic order. Ventrolaterally there is an area with variable, long latency responses and no apparent frequency axis.
Acoustic radiation from fluid-loaded structures with discontinuities
Authors: Thompson Charles , Sen Rahul
Published: October 2005

The presence of discontinuities, such as joints, in a fluid-loaded structure results in farfield acoustic radiation even when subsonic wavenumbers prevail in the main body of the structure. The object of this study is to develop a rational model of this phenomenon using singular perturbation methods. When a flexural wave in a thin structure impinges on a joint, evanescent structural displacement fields are set up in the vicinity of the joint. It will be shown that these fields are associated with rotation-dominated modes that are supported by shear-corrected plate theories of the Timoshenko-Mindlin type flexural mode. The method of matched asymptotic expansions will be used to obtain mode-conversion coefficients, and it will be shown that the spacial wavenumber spectrum of the local field is instrumental in setting up an acoustic farfield in the surrounding fluid. An important mathematical issue is the proper description of evanescent fields; the analysis will be based on results obtained previously in connection with acoustic waveguides.
The acoustic radiation from a semisubmerged elastic cylinder
Authors: Jouaillec François , Jacquart Guillaume
Published: October 2005

A large number of techniques have been developed to predict the acoustic radiation of totally immersed elastic structures, but they have not been applied to surface piercing bodies. The case of an infinite elastic cylinder, governed by Donnell's equations, is first considered, its axis lying on the pressure release surface. An analytic theory is derived, and applied to give the radiated field due to a point force excitation. The position of the excitation point with respect to the free surface is discussed as well as the differences between the partially loaded and the totally immersed cylinder. Then a numerical method based on finite elements and integral equations is presented and applied to the case of the partially immersed finite cylinder.
Comparison of two LP parametric representations in a neural network-based speech recognizer
Authors: Paliwal K. K.
Published: October 2005

Although the different linear prediction (LP) parametric representations provide equivalent information about the short-time spectral envelope of speech, these representations are known to show differences in their speech recognition performance when used with conventional linear pattern classifiers. Recently, an error backpropagation algorithm has been reported in the literature for training the artificial neural networks, and it has been shown that the multilayer perception (MLP) classifiers that are nonlinear in nature can provide arbitrarily shaped decision surfaces in the multidimensional pattern space. The aim of the present paper is to see whether the different LP parametric representations show differences in their speech recognition performance for these nonlinear MLP classifiers, also. For this, the two-, three-, and four-layer perception classifiers are studied for the following two LP parametric representations: (1) the LP coefficient representation and (2) the cepstral coefficient representation. The results for the conventional linear pattern classifiers are also provided for the sake of completeness. It is shown that, like the conventional pattern classifiers, the MLP classifiers also result in better recognition performance for the cepstral coefficient representation than for the LP coefficient representation.
Optimization of a low-frequency transmitting array
Authors: Lalisse Dominique , Boucher Didier
Published: October 2005

A low-frequency plane array is studied in water in a wide frequency band around the resonance frequency of the transducers. The array under study is made of eight length-expander vibrators (two columns of four transducers) with a circular radiating face in a rigid box of limited dimensions. The radiating impedance matrices are calculated by an integral equation method [C. Audoly, J. Acoust. Soc. Am. Suppl. 1 83, S20 (1988)] and projectors are modeled with a classical electromechanical equivalent circuit. Due to the effects of acoustic interactions, no terms in the matrices are found to be negligible. Mechanical and electrical constraints on the transducers are identified and computed. The array is studied under three conditions: identical voltage driving, identical headmass velocity distribution, and acoustic power optimization. The results confirm that acoustic interactions have important and drastic effects around the resonance. The study of acoustic power optimization makes it possible to discuss the opportunity of using velocity control and electromechanical feedback devices in low-frequency sonar projector arrays.
The increase of transducer directivity using diffractive attachments
Authors: Woszczyk Wieslaw R.
Published: October 2005

Increased directivity is sought for pressure microphones at frequencies above 1 kHz in order to accomplish useful directional selectivity and better signal-to-noise ratio in the pickup of direct transient information contained within reverberant sound fields. The goal is to improve the “reach” of pressure microphones for direct transient sound under reverberant conditions in rooms while maintaining only single-point sampling of the sound field. Smooth off-axis frequency responses and undistorted time-domain responses of microphones are desired to transcribe with fidelity the complex sound field at the point of pickup. Diffractive and absorptive attachments are installed on microphones to modify their frequency and directional responses without distorting time-domain responses. Detailed directional frequency responses and transient responses are measured at every 5 and 15 deg of angular sound incidence using impulse techniques to verify the effect of the attachments. These responses are compared to those of high-quality microphones used for the recording of music and speech. [Work supported by SSHRC.]
Modern techniques for frequency response measurement of loudspeakers
Authors: Yoshikawa Shokichiro , Wakuri Takashi
Published: October 2005

Usually, the frequency responses of loudspeakers are measured by the point-by-point method in a free sound field. In this method, accuracy of the measurement depends on the precision of the free sound field. Since the wavelength of sound is quite long in the low-frequency range, an anechoic room of a large size with high accuracy is required to obtain good results in the low-frequency range. To overcome this difficulty, several new measuring methods have been proposed [e.g., J. Merhaut, J. Audio Eng. Soc. 30, 882 (1982); and IEC84/WG8 (Chairman) 1 April (1984)]. In this study, a comparison and evaluation of new measuring methods were carried out. Factors that affect the accuracy of measurement were investigated. The accuracy and the applicable frequency range were clarified. The possibility of measuring the frequency response of loudspeakers without using an anechoic room will be discussed.
A balanced, centrally stiffened design for PVDF hydrophone arrays
Authors: Ting Robert Y. , Geil Fred G.
Published: October 2005

As PVDF thick films become more readily available, there has been a growing interest in the development of a large-area hydrophone for passive sonar applications. These new PVDF materials offer the advantages of having a lower density, greater mechanical strength and flexibility, and better impedance match to water than conventional piezoelectric ceramics. Furthermore, they are now available in large sheets, from which arrays can be developed for acoustic detection covering large surface areas. Prototype PVDF hydrophone arrays were fabricated and tested to show that in-plane flexural motion greatly affected hydrophone responses due to the in-plane anisotropy of the piezoelectric properties of PVDF. To circumvent this difficulty, a balanced, centrally stiffened configuration was adapted by sandwiching two pieces of PVDF to a common damped plate, while aligning in parallel the stretched “3—1” directions of the PVDF sheets. With this design, constant receiving sensitivity and directivity patterns in agreement with theoretical predictions were obtained. Further refinement of this design was also achieved through mathematical modeling. [Work supported by ONR.]
A study of the mechanical property of materials using acoustic microscopy
Authors: Yamanaka Kazushi
Published: October 2005

The interpretation of the general features of acoustic microscopy images is discussed in conjunction with its application to materials science under the following topics. (1) Interference fringes have been discovered around surface breaking cracks, and a model based on the leaky Rayleigh wave has been proposed. It has attracted a considerable amount of interest because these fringes might give new information on the elastic properties of microscopic discontinuity such as cracks, grain boundaries, and steps that are almost normal in sample surfaces. (2) When subsurface cracks are close to parallel to the sample surface, they can be analyzed by a simple plate model with water or air below. Either the V(z) curve measurement or the resonance method is useful depending on whether the frequency-depth product is much smaller or close to the first cutoff of the higher-order modes of the leaky Lamb waves. This analysis was successfully applied to a study of indentation fractures of steel ball bearings in use. (3) Image observation and the leaky SSCW velocity measurement at 775 MHz have been applied to individual spherulites in semicrystalline polypropylene. Through the signal processing of the V(x,z) image, it has been found that the difference in velocity between spherulites with different thermal histories can be larger than 30%.
Detection of quantization distortion in digital audio systems
Authors: Maeda Kanako , Usagawa Tsuyoshi , Ebata Masanao
Published: October 2005

In recent digital audio systems, 16-bit uniform quantization is employed in most cases, because a dynamic range of 96 dB is considered satisfactory for most cases. Ideally speaking, a dynamic range of more than 120 dB is required in music reproduction. However, harmonic distortion due to quantization can be detected when fewer bits are used for the representation of the digital signal that is reproduced at a higher sound level. In this paper, the thresholds of distortion are measured using a stationary tone as a function of sound level, the bit width of the signal, and the tone spectrum. Whether harmonic distortion is detectable when the maximum level of 16-bit digital signal is set at 120 dB SPL is examined. The effect of a dither is also examined. The results show that the dither is not always effective in reducing distortion. Furthermore, using a complex tone with exponential decay, thresholds for various conditions are measured and the results from the viewpoint of masking effects are discussed.
Numerical calculations of echo patterns in ultrasonic detection
Authors: Donglin Li , Chongcheng Cai , Nanxiang Jiang
Published: October 2005

A calculation method has been developed to calculate the echo patterns of an ultrasonic pulse in the time domain. Another method for forming the acoustic radiation impedance function of the ultrasonic transducer used will also be presented. Typical numerical results are compared with experimental data, and they are in good agreement with each other.
Quantitative measurement capabilities of the scanning laser acoustic microscope
Authors: O'Brien William D.
Published: October 2005

The scanning laser acoustic microscope (SLAM) has the capability of determining the spatial distributions of attenuation coefficient and speed in materials under evaluation. The attenuation coefficient is determined by the insertion loss procedure [K. M. U. Tervola et al., IEEE Trans. Sonics Ultrason. SU-32, 259–265 (1985)], which compares the received signal amplitude of a specimen of known thickness in the sound path with that of the reference medium. The entire image is broken into 64 subimage areas, each of approximately 400 uμm × 250 uμm in size. This subarea image is used to determine the insertion loss. The slope of the linear least-squares fit line for an insertion loss versus specimen thickness plot yields the attenuation coefficient. Using known materials, the attenuation coefficient accuracy and precision are −+ 12% and −+ 5%, respectively. Ultrasonic speed is determined from the interference mode image by way of the spatial frequency domain technique [K. M. U. Tervola and W. D. O'Brien, Jr., IEEE Trans. Sonics Ultrason. SU-32, 544–554 (1985)]. The image's field of view (3mm × 2 mm) contains approximately 39 vertical interference lines equally spaced about 85 uμm apart. The speed of sound is determined by the horizontal shift of the interference lines between the reference medium and the specimen. Again, using a known material, the speed accuracy, and precision are −+ 2.9% and −+ 0.4%, respectively. Smaller regional differences can be distinguished with the speed analysis than the attenuation coefficient analysis. Each speed pixel is approximately 4 uμm × 8 uμm and a speed profile (80 uμm × 2 mm) along the vertical direction of the image is generated. In contrast, in each insertion loss pixel (400 uμm × 250 uμm), an average insertion loss value per section is generated over a region approximately 1 mm × 1 mm in extent. Further, at least three separate sections are required to calculate the attenuation coefficient. The application of SLAM towards an understanding of ultrasonic interaction action with biological materials is being studied by a number of different animal and tissue models. These models consider both normal and pathologic, homogeneous and heterogeneous, and soft and hard tissues. [Work supported by NIH Grants AM21557, CA30629, and AR36794.]
Recent developments in ultrasonic nondestructive evaluation in Japan
Authors: Fukuoka Hidekazu
Published: October 2005

Ultrasonic nondestructive evaluation is one of the most powerful tools among many nondestructive evaluation procedures and plays an important role in the on-line manufacturing process and postprocess material testing. Recent developments in this field in Japan at universities, government laboratories, and industrial laboratories are surveyed. The behavior of ultrasonic waves in solids is vividly understood by both computer simulation and stroboscopic photoelastic visualization and it provides a fundamental basis of quantitative information for sizing flaws. The acoustoelastic measurement of residual stress in structural components allows us to estimate their service-life expectancy. By the acoustoelastic evaluation of texture in steel, an ultrasonic pole figure is obtained more conveniently than with the x-ray method. As industrial applications, there are the laser generation and detection of ultrasonic waves, the detection of surface defects and internal voids in ceramics, phased array transducers and their application for steel pipe testing, and on-line wall thickness measurements using an electromagnetic acoustic transducer for hot seamless steel pipes. The acoustic microscope also has many applications in the nondestructive evaluation of materials.
Application of ultrasonic computed tomography to nondestructive inspection of SiO2 ingot material qualities
Authors: Yamada Hiroaki , Tomikawa Yoshiro , Nishida Mitsuhiro
Published: October 2005

It is very important industrially to produce SiO2 chips with uniform material qualities for integrated circuit elements (IC). Therefore, nondestructive inspection to detect whether the material quality of the SiO2, column ingot is uniform or not is necessary before it is cut into a small chip for IC elements. For this purpose, the x-ray CT technique is effective. However, the technique is dangerous for workers in usual factories. Therefore, ultrasonic CT was tried for such detection. The ultrasonic CT was already developed using data from the time of flight (TOF) and applied to certain cases; for example, nondestructive inspection of rotten parts or hidden knobs in a cedar log and the measurement of internal temperature distribution. In this paper, an attept was made to use the ultrasonic CT for the nondestructive inspection of SiO2 column ingots. The experiment was made with an ultrasonic transducer at 5.0 MHz. The results show the usefulness of the TOF ultrasonic CT for the nondestructive inspection of SiO2 column ingots.
Distortion-product emissions in humans with high-frequency sensorineural hearing loss
Authors: Harris Frances P. , Glattke Theodore J.
Published: October 2005

Distortion-product emissions (DPEs) were detected in 20 adults with pure-tone behavioral threshold elevation at frequencies above 1000 Hz and in 20 adults with normal hearing. Equilevel pure tones at f1 and f2 (f2/f1 approximately 1.21) ranged from 65 to 20 dB SPL and were located at frequencies that approximated audiometric frequencies from 750 to 8000 Hz. DPEsat 2f1 − f2 ranged in amplitude from 23 to −18 dB SPL and were from 30 to 60 dB below the primaries for subjects with normal hearing. DPE amplitudes, response ranges, and slope values were significantly different between the two groups when the primaries were in the high-frequency region, but were similar at 0.75 and 1 kHz. DPEs were present for frequencies at which pure-tone behavioral thresholds were less than 15 dB HL and were absent or significantly attenuated if threshold exceeded 50 dB HL. The amplitude and range of DPE responses varied considerably when behavioral thresholds were between 20 and 45 dB HL. Results are compatible with similar findings from experimental animals.
Fundamental observations for tinnitus
Authors: Tanahashi Teiji , Tsuzuki Koichi , Tanahashi Atsushi
Published: October 2005

Changes in the spontaneous discharges of the auditory neuron in the cochlear nucleus were analyzed under various conditions. Young adult cats were anesthetized with pentobarbital, pentazocine, and diaxepam. Characteristic frequency, threshold, PST histogram, and the spontaneous discharge rate of each neuron were obtained before and following asphyxia. EEG, ECG, and blood gas content were also analyzed. Following asphyxia, lasting from 60–110 s, the spontaneous discharges increased markedly in ten neurons, but in five neurons, the increase was slight or nonexistent. The spontaneous discharge of the auditory neuron in the cochlear nucleus following asphyxia was temporarily suppressed by the administration of Lidocaine or Diltiazem. This effect was observed continuously for over 3 h. The dose effect was also examined.
Behavior specific vocalizations of two Atlantic bottlenose dolphins (Tursiops truncatus)
Authors: Partan Sarah , Jerger Kristin , Xitco Mark , Roitblat Herbert , Herman Louis , Williams Humphrey , Hoffhines Michael , Gory John , Ralston James
Published: October 2005

The vocalizations of two Atlantic bottlenose dolphins (Tursiops truncatus) were recorded during a study of behavioral mimicry. Underwater recordings were made on one channel of a stereo magnetic tape, while a behavioral trial-by-trial narrative was recorded onto a second channel. The tapes were analyzed by human listeners blind to the behavior performed. The vocalizations were divided into categories of pulsed versus nonpulsed (whistle) sounds. There was a significant dependency between vocalizations produced and behaviors performed (χ2 = 320.48, df = 60, p < 0.00001). This finding suggests that the dolphins may communicate behavior specific information in their vocalizations. The results of current spectrographic and further behavioral studies will also be presented, with the objective of determining whether the vocalizations are communicative or are artifacts of the behavior.