bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual differences in cyclical and speech movement
Authors: Perkell Joseph S. , Zandipour Majid , Matthies Melanie L.
Published: July 2002

A comprehensive account of speech production should explain interspeaker variation. Toward this end, a study was performed with eight speakers to investigate whether individual kinematic performance limits, as reflected in a speechlike cyclical task, could account for differences in speech kinematics. Kinematic data from cyclical CV movements at rates from 1–6 Hz of the lower lip, tongue blade, and tongue dorsum were compared with data from speech utterances in different conditions, including normal, fast, clear, and slow. There were differences in movement distance, peak velocity, and duration among the speaking conditions and among the speakers. Three speakers produced ‘‘clear’’ speech utterances with distances, peak velocities, and durations that were greater than normal. The data from two of the three may reflect some increased effort for clear speech. The amount of overlap of the speech data and cyclical data varied across speakers, ranging from little overlap to complete overlap. Thus, in general, the cyclical task did not define a kinematic performance space within which speech movements were confined. These results will be discussed in relation to differences between the tasks, possible interactions between production and perception, and possible differences in motor and/or perceptual performance capacities. [Work supported by NIDCD.]
Adaptive beamforming for underwater acoustic communication in shallow water
Authors: LeBlanc Lester R. , Alleyne Jochen R. , Beaujean Pierre P.
Published: July 2002

An adaptive beamformer was developed for use with existing underwater acoustic modems and for measurement of the underwater acoustic communication channel. The output of the beamformer is made up of many independent channels, each derived from the application of orthogonal vectors to the array elements. Each channel represents a vertical beam that is focused in the direction of correlated energy arriving at the array of vertically spaced transducers. Within each beam, nulls are created in the direction of interference. Experiments were conducted in shallow water to characterize the acoustic communication channel at many frequencies and ranges so as to evaluate modem performance using various encoding methods and waveforms. It was found that high-reverberation levels exist at our test site in the shallow water near the shore environment. In this environment, adaptive processing reduced reverberation and transmission errors significantly. Wideband PSK was used to evaluate channel characteristics. In the process of testing the adaptive beamformer, waveforms were developed for a low-cost single-channel modem for use on AUVs. Results of the adaptive beamformer and the single channel modem are presented. [Work supported by ONR.]
Detections of singing humpback whales (Megaptera novaeangliae) across the northeast Pacific during the SWAPS97 sperm whale cruise
Authors: Norris Thomas F. , Barlow Jay , McDonald Mark
Published: July 2002

The NOAA Southwest Fisheries Science Center conducted a 3-month (8 March–9 June 1997) Sperm Whale Abundance and Population Structure (SWAPS97) cruise to visually and acoustically survey sperm whales in the northeast Pacific. A custom-designed towed hydrophone array system was deployed to detect and determine bearings to sperm whale ‘‘clicks.’’ However, this system also proved effective in detecting and recording songs of humpback whales. Additionally, sonobuoys were deployed regularly throughout the cruise to monitor and record baleen whales’ sounds. The timing and location of these surveys corresponded well with the northbound migration of humpback whales from known tropical breeding areas to northern latitude feeding areas and resulted in numerous (∼130) detections of singing humpback whales. Most of these detections occurred in pelagic waters (i.e., away from breeding areas), indicating that humpback whales sing during their northward migration. Of greater interest were clusters of detections 400–600 miles off the coast of California. It is possible these detections correspond to animals migrating north from the Revillagigedo Islands, Mexico. Data on singing humpback whales collected during the SWAPS97 cruise will be summarized, and implications regarding the biology and management of humpback whale populations will be discussed. [Work supported by NOAA/NMFS and ONR.]
Broadband characteristics of spinner dolphin (Stenella longirostris) social acoustic signals
Authors: Lammers Marc O. , Au Whitlow W. L. , Aubauer Roland
Published: July 2002

A predisposition generally exists among delphinids for hearing high-frequency signals, raising the question: How much do dolphins actually use the ultrasonic range for social signaling? To answer this question, a low-budget, portable broadband recording system was developed to collect whistles and burst pulses from a population of Hawaiian spinner dolphins resident off the leeward coast of Oahu, Hawaii. This system employs a PCMCIA A/D converter to digitize signals directly into a laptop computer and has a maximum upper frequency limit of 140 kHz. Signals collected using this system reveal that spinner dolphins use the ultrasonic range extensively. Although the fundamental frequencies of whistles tend to be restricted below approximately 23 kHz, strong harmonics are often clearly visible up to 70 kHz. Even more high frequency in nature are the burst pulses. These signals often have little or no energy below 20 kHz and can extend beyond the recording limits of the system. Furthermore, high-frequency burst pulses are pervasive in the acoustic output of spinner dolphins, making it reasonable to assume that the ultrasonic range may, in fact, be important not only for echolocation, but also social signaling purposes.
Aspect-independent classification of ‘‘dolphin’’ ensonified mines using Choi–Williams representations
Authors: Helweg David A. , Moore Patrick W. B.
Published: July 2002

Contemporary anti-invasion mines have aspect-dependent shapes, making discrimination of mines from nonthreat objects, and classification of mines, a difficult task for human mine countermeasures personnel. Shallow-water (SW) noise and bottom reverberation substantially degrade the acoustic structure of mine echoes. Traditional MCM target strength and FFT classifiers are not effective under these conditions. The testing of a novel neural network classifier to solve the task of classifying mines in the SW acoustic environment was begun. Three mine types were ensonified at 1 deg rotations using synthetic dolphin clicks. A learning vector quantization network was trained to classify the mines using the Choi–Williams joint time-frequency distributions of echoes. A training set of 36 echoes per mine (5, 15, 25,..., 355 deg) was created, with the remaining echoes (0, 10, 20,..., 350 deg) reserved for generalization testing. The network correctly classified the mines at novel orientations with 85% accuracy. Performance using CWD will be contrasted with biomimetic sonar target classifiers under varying signal-to-noise ratios. [Research funded by ONR Underseas Active Signal Processing Program.]
Modeling of penetration of dolphin sonar clicks into ocean sediments
Authors: Chotiros Nicholas P.
Published: July 2002

The penetration of dolphin sonar clicks into the ocean sediment is modeled using Biot’s theory of sound propagation in porous media. A range of sediment types are considered, from soft mud to sand. The expected signal loss as a function of depth and grazing angle are computed. At any given value of loss, the penetration may vary by more than an order of magnitude depending on sediment type. The penetration is modified by critical angle effects and interference between different sediment acoustic waves. In modeling the acoustic scattering from buried objects, it is not sufficient to compute the net acoustic pressure, but also the pressures of each contributing sediment acoustic wave component. [Work supported by ONR code 342.]
Classification of dolphin echolocation clicks by means of energy and frequency distributions
Authors: Houser Dorian S. , Helweg David A. , Moore Patrick W.
Published: July 2002

Echolocation clicks (N∼30 000) were collected from an Atlantic bottlenose dolphin (Tursiops truncatus) performing object discrimination tasks. Eight categories of clicks were identified using the spectral conformation and relative position of −3- and −10-dB peaks. A counter-propagation network utilizing 16 inputs, 50 hidden units, and 8 output units, was trained to classify clicks using the same spectral variables. The network classified novel clicks with 92% success. Additional echolocation clicks (N>24 000) from two other dolphins were submitted to the network for classification. Classified echolocation clicks were analyzed for animal-specific differences, changes in predominant click type within click trains, and task-related specificity. Differences in animal and task performance may influence click type and click-train length.
B-scan ultrasound monitoring of cavitation acitivity in and around the kidney during shock wave lithotripsy
Authors: Cleveland Robin O. , Crum Lawrence A. , Lifshitz David A. , Connors Bret A. , Willis Lynn R. , Evan Andrew P. , Lingeman James E.
Published: July 2002

Acoustic cavitation is thought to play a major role in both stone comminution and tissue injury during shock wave lithotripsy (SWL). Although ultrasound machines cannot directly observe cavitation events, remnant gas bubbles appear as echogenic regions. We treated young pigs in an unmodified Dornier HM3 and used a standard clinical ultrasound machine (Brüel and Kjær 3535) to image the kidney while SWL was being administered. We observed large regions of in vivo echogenicity within the renal pelvis (collecting system), which has not been reported before. When the ureter was blocked, up to 30% of the renal pelvis was covered with echogenicity. Clouds of echogenicity progressed through the collecting system with consecutive shots. The echogenic regions in the renal pelvis could be temporarily enhanced when nondegassed fluid was injected through a ureter catheter. Echogenicity was observed on the posterior and anterior surfaces of the kidney and appeared to occur at sites of subcapsular hematomas. The presence of echogenicity is consistent with the claim that cavitation plays an important role in both stone comminution and tissue damage. [Work supported by NIH and the Hunt Fellowship.]
Method of pathology recognition in bio-organs by multifrequency ultrasound signals
Authors: Oboznenko Lena I.
Published: July 2002

Ultrasound methods of pathology recognition in bio-organs are proposed. They are based on the application of multichannel sounding signals (or wide band signals). The peculiarities of the proposed methods take into account the specific character of the biomedium in the ultrasound diagnostic. The nuances of the effective application in the ultrasound diagnostic of the following method of recognition are analyzed: application of the natural resonance frequencies of the bio-organs without signal form recollection (vessel, red corpuscles, leucocytes, etc.), by apportionment of complex poles of the Laplas transformation function (R. Prony’s method), application of the stepped influence with organ boundary restoration by impulse reaction and by the algorithm of the form restoration with projection (J. Young’s method and V. Bojarsky’s method, J. Radon transformation), structure methods of the two-dimensional bio-organ form picture (the grammar method), multichannel irradiation of the bio-organ with its phase-frequency characteristic synthesis of three-dimensional bio-organ transformation by its Ess. in LF, MF, HF bands. The numerical data concerning the form compensation of the spherical and elliptical elastic objects and recognition of the red corpuscles and leucocytes in blood vessels are deduced. Frequency band: 1–10 MHz, feeler length: one period, discrete radiation: 1, 2, 4, 6, 8, 10 MHz.
Reliable high-temperature electronics for instrumentation and data acquisition
Authors: Gingerich Ben
Published: July 2002

Honeywell is developing and has introduced the first products of the HTMOSTM product line, which is targeted for use in systems operating in severe high-temperature environments. The HTMOSTM line of electronic products incorporates Honeywell’s oxide-isolated high-temperature process and high-temperature circuit design methodologies. These components are being developed to meet applications in instrumentation, data acquisition, and control where hostile environments require a large temperature range of −55 to +225 °C with an extended operating life of 5 years at elevated temperatures. Honeywell has introduced a quad operational amplifier, quad analog switch, an 8-bit microcontroller, and a 32 K×8 SRAM. Additional products are planned for introduction in 1997. This paper will discuss the high-temperature features of the silicon on insulator (SOI) process technology and product design approaches for reliable high-temperature electronic components. The paper will also discuss the existing product performance in a high-temperature environment.
Comparison of a thermally biased PMN-PT transducer and a conventional PZT-based underwater source
Authors: Hudson Scott A.
Published: July 2002

Recent research into PMN (lead magnesium niobate)-based electrostrictive materials have led to compositions with strain rates significantly higher than that of piezoelectric ceramics. The large strain rate makes it ideal for use in high-power SONAR transducers. However, unlike piezoelectric ceramics, the properties of PMN vary nonlinearly with temperature. The highest performance PMN compositions exhibit optimal characteristics at temperatures near 85 °C. AlliedSignal has solved the engineering challenges of implementing a high-temperature PMN composition in a SONAR transducer and demonstrated the performance at NUWC Lake Seneca test facility. This paper discusses the properties of high-temperature PMN materials and presents the test results of a PMN transducer compared with a similar transducer which utilizes conventional piezoelectric ceramic. The PMN transducer produced roughly 6 dB higher source level than the PZT transducer. Electromechanical coupling and bandwidth of the two transducers was similar.
Development of an advanced vibratory source for borehole seismology
Authors: Paulsson Bjorn N. P.
Published: July 2002

Single-well seismology, reverse vertical seismic profiles (RVSP’s) and Crosswell seismology are three new seismic techniques for obtaining much higher resolution images of oil and gas reservoirs than what is currently obtainable with surface seismic techniques. Borehole seismology involves inserting both the source and the seismic receivers in oil or gas wells. In the past these methods have been limited to short distances between source and receivers in shallow wells. In 1997 a new borehole seismic source and receiver system has been deployed with a capability of handling source–receiver spacings of more than 2000 m in rock with a Q value of more than 20, and well depths as great as 6500 m. This advanced borehole seismic data acquisition system consists of a powerful, clamped, swept-frequency, vibratory source which is nondestructive, a multilevel receiver string of clamped, three-component geophones, and an acquisition system for reverse VSP’s. The downhole vibrator produces high-quality S waves, with controlled polarization, as well as P-wave direct arrivals and reflections. This paper discusses the design and performance of this system.
Auditory temporal microstructure: Evidence of under- and over-shoot at onset and offset of a narrow-band noise masker measured in an off-frequency masked detection task
Authors: Formby Craig , Ferguson Sarah H. , Heinz Michael G.
Published: July 2002

Detection thresholds were measured as a function of the temporal position of a 5-ms sinusoidal signal presented within one of two 500-ms observation intervals. Both intervals contained a 400-Hz-wide noise masker, logarithmically centered at 2500 Hz, that was gated on at 150 ms and off at 350 ms within each interval. The signal and masker were both gated with 2-ms linear ramps. The level of the signal was tracked adaptively in blocks of forty 2I 2AFC trials to estimate a 70.7% correct detection threshold. Thresholds were measured at 43 temporal signal positions within the observation interval, with detailed sampling around the onset and offset of the masker to assess temporal edge effects. Experiments to date with four listeners have focused on signals presented at 1900 or 2100 Hz. The temporal microstructure of the detection functions has characteristically revealed a complex pattern of under- and over-shoot (i.e., enhanced and diminished detection, respectively). These effects, which have been observed at both the onset and offset of the masker for virtually all masker spectrum levels between N0=0 and 70 dB, may accentuate the temporal edges of the masker and, in general, enhance detection of acoustic onsets and offsets. a)Currently at Dept. of Speech and Hearing Sci., Indiana Univ.
New parameters and mapping relations for the HLsyn speech synthesizer
Authors: Hanson Helen M. , Stevens Kenneth N. , Beaudoin Robert E.
Published: July 2002

HLsyn is a quasiarticulatory speech synthesizer in which a small set of parameters control a Klatt synthesizer [Stevens and Bickley, J. Phon. 19 (1991)]. Originally, ten parameters were used. In this paper three new physiologically based parameters, together with some additional modifications, are described. The first is a time-varying subglottal pressure parameter, which provides the user with additional control of the voice-source amplitude. It can also be used to turn on voicing, and it has an influence on fundamental frequency. The second parameter is a time-varying percentage change in the compliances of the vocal-tract walls and vocal folds. This parameter can, for example, be employed when synthesizing voiced obstruents: increasing it results in facilitation of glottal vibration and lowering of the fundamental frequency. The third parameter is the time-varying cross-sectional area of a posterior glottal chink. Because it is independent of the area at the membranous folds, significant noise-source amplitudes can be achieved during voiced speech. Thus one can synthesize aspirated voiced stops, as well as breathy speech, in a natural manner. Finally, a default female voice and an intrinsic pitch feature have been added to the system. Examples of copy synthesis where the new parameters play a role are presented. [Work supported by NIH Grant MH52358.]
Indexical cuing in laughter
Authors: Bachorowski Jo-Anne , Smoski Moria J. , Owren Michael J.
Published: July 2002

Laughter is a frequently produced yet poorly understood vocal signal. Despite the lack of basic knowledge regarding this species-typical vocalization, this signal may be advantageous to study as it provides an opportunity to examine indexical cueing in the absence of linguistic content. The source-filter model of vowel production guided acoustic analysis of laughter recorded from experimentally naive subjects as they watched emotion-inducing film clips in a laboratory setting. Subjects were 48 males and 48 females tested either alone or with a same- or opposite-sex friend or stranger. Laugh acoustics were found to vary by gender, talker, and social context. Males produced predominantly unvoiced, ‘‘grunt’’ laughs, whereas female laughter was more variable and included more voiced, long duration ‘‘song’’ laughs. Discriminant function analyses revealed that source and filter-related cues were differentially associated with social context and talker identity. Variability in source-related cues, particularly F0, more successfully discriminated social context, whereas cues related to the vocal tract transfer function better discriminated among individuals. Females, but not males, had significantly higher formant frequencies when tested with opposite-sex strangers. The overall pattern of results is consistent with recent examinations of indexical cuing in human speech and nonhuman primate vocalizations. [Work supported by NIMH.]
On the meaning and the accuracy of the pressure-flow technique to determine constriction areas within the vocal tract
Authors: Pelorson Xavier , Fahas Salima , Badin Pierre
Published: July 2002

Since the work of D. W. Warren and A. B. Dubois [Cleft Palate J. 1, 52–71 (1964)] was published, the ‘‘pressure-flow technique’’ has been widely used to estimate constriction areas within the vocal tract. However, two fundamental questions regarding this technique have not been clearly addressed: (1) What is exactly measured (minimum, maximum, or ‘‘mean’’ areas)? (2) Which accuracy can be expected from this technique? A theoretical and experimental study based on a vocal tract mechanical model, including various constriction shapes, is presented. Compared with much more complex viscous flow solutions, a simple one-dimensional flow model is shown to yield fair estimates of the areas (within 10%), except for low Reynolds numbers. The empirical head-loss factor K=0.67, sometimes used, appears meaningless and is probably due to an experimental artefact. The pressure-flow technique is shown to be relatively insensitive to the exact constriction shape (converging, straight, or diverging), and the estimated area to be close to the minimum area of the constriction. This result can be theoretically rationalized by considering that in all cases studied here the flow separation point is always close to the minimum constriction. Extensions and limits of these conclusions for unsteady flows will also be discussed.
Voiced excitation functions calculated from micropower impulse radar information
Authors: Burnett G. C. , Gable T. J. , Holzrichter J. F. , Ng L. C.
Published: July 2002

Efforts underway at the Lawrence Livermore National Laboratory to use newly designed micropower impulse radars (MIR) to measure in real time the excitation function of the vocal tract will be presented. Studies undertaken in collaboration with the University of California at Davis and the University of Iowa with high-speed laryngoscopic cameras, electroglottographs, flow masks, and subglottal pressure transducers have solidified the relationship between the signal returned by the MIR and the voiced excitation function of the vocal tract. As a result, for the first time a transfer function of the vocal tract can be calculated in real time and with unprecedented clarity for voiced speech. This new capability could have significant implications for improvements in speech recognition and speech synthesis processing.
Plane wave reflection coefficient estimation by use of spatial parametric signal modeling
Authors: Kwon Hyu-Sang , Bolton J. Stuart
Published: July 2002

The plane wave reflection coefficient of an absorbing infinite plane can be estimated from pressure distributions on two lines parallel to the surface. The measured pressures are decomposed into incoming and outgoing plane waves in the wave-number domain after the Hankel transform is applied to the spatial data. In practice, only a finite number of pressure measurements can be made on the measurement lines. As a result, errors resulting from aliasing and truncation are induced in the wave-number spectra and subsequently the reflection coefficient. The aliasing results from insufficiently small sample spacing, and can be easily controlled. The truncation error results from the limited size of the measurement aperture, which may be difficult to expand for practical reasons. Therefore, extrapolation techniques based on parametric signal modeling have been developed to ‘‘virtually’’ expand the measurement aperture, thus minimizing truncation effects. However, some restrictions, particularly on spatial sampling rate, must be considered in order to obtain good estimates of the reflection coefficient. Prony series modeling is one procedure that can be used to model and extrapolate the spatial sound pressure data. Reflection coefficients estimated by using the Prony series approach will be used to illustrate this procedure.
Range-dependent multitone matched-field processing in SWellEX-3
Authors: Schey Phil W. , Booth Newell O. , Bachman Richard T. , Hodgkiss William S.
Published: July 2002

SWellEX-3 was an experimental study of shallow-water propagation and matched-field processing conducted 10 km off San Diego in July, 1994. Data were recorded on a 64-element, 118-m aperture vertical line array anchored in 200 m of water. A cw source emitting tonals from 53–197 Hz was towed over tracks where the water depth varied from 200–75 m. Examples of range-dependent matched-field processing of this multitone signal using the finite-element parabolic equation program for propagation modeling will be presented.
Acoustical modeling and simulation in the 1960s: Paul Veneklasen’s quest for ‘‘envelopment’’ and correlations with auditorium design
Authors: Hyde Jerald R.
Published: July 2002

Paul’s favorite ‘‘in-house’’ project in the 1960’s was his auditorium synthesis system. He devised an electro-acoustic laboratory listening environment which simply divided a test sound field, excited by an anechoic recording, into the three basic components called ‘‘direct,’’ ‘‘envelopment,’’ and ‘‘reverberance.’’ The envelopment factor was the summation of early delayed reflections which surrounded the listener at the sides via loudspeakers. Paul was primarily looking for how much envelopment, or lateral early energy, a listener preferred relative to the direct sound level. At around the same time, he was using a nitrogen jet ultrasonic noise source to model test exactly how much lateral early energy was possible. He found that in a conventional hall with the best possible lateral energy design, the amount of envelopmental energy available at most seats was around 3 to 5 dB lower than ‘‘desired.’’ Concurrently, Marshall and then Barron extended the previous work of Keet and Kuhl in developing the parameter called ‘‘lateral energy fraction,’’ which essentially quantified Veneklasen’s envelopmental energy. Computer systems later allowed the actual measurement of typical lateral energy values in concert halls. Veneklasen’s findings will be compared to the actual measured values for hall’s of well-known quality.
Paul Veneklasen and the design and engineering of the dampened mild carbon steel stage acoustic shell: A reminicence
Authors: Izenour George C.
Published: July 2002

Paul and I were introduced to each other in the early 1960s by Vern Knudsen with whom I was then collaborating on Frank Lloyd Wright’s last public building, The Grady Gammage Auditorium on the Campus of Arizona State University (1964). My initial collaboration with Paul, with Vern Knudsen looking over both our shoulders, was the multipurpose arena on the campus of Washington State University. Simultaneously with the Washington State Project (1973) there were two other collaborations: (1) the remodeling-restoration of the Eastman theater on the campus of the University of Rochester (1972) and (2) the Hancher auditorium on the campus of the University of Iowa (1973). All told, my three collaborations, with Paul as acoustics consultant and myself as theater consultant, extended over a period of about 5 years (1968–1973). It is our collaboration on the Eastman project that is the subject of this paper.
Desert tortoises (Gopherus agassizii) lack an acoustic startle response: Implications for studies of noise effects
Authors: Bowles Ann E. , Eckert Scott A.
Published: July 2002

The startle reflex is little studied in nonmammalian vertebrates, but in mammals it is often characterized by increase in heart rate. Orienting can also occur, characterized by a brief decrease in heart rate. To determine whether these responses occur in a testudinate, the desert tortoise, heart rate and behavior were measured during exposures to simulated jet overflights (94.6–114.2 dB CSEL) and sonic booms (6–10.5 psf). The best sensitivities of the 14 subjects ranged from 23 dB–50 dB SPL (average 34 dB SPL at 250 Hz) measured using ABR. Initial exposure to simulated jet overflights produced a typical reptilian defensive response: freezing. Tortoises became totally immobile for periods of up to 113 min. The average heart rate showed a gradual decline (7–8%), recovering within 2–4 h. Tortoises oriented when exposed to simulated sonic booms and after repeated exposure to subsonic aircraft noise; orienting produced no detectable change in heart rate. These results suggest that (1) high-intensity transients affect desert tortoises by altering activity patterns, but do not have a direct effect on heart rate and (2) tortoises experience a physiological response that produces protracted freezing. [Work supported by USAF, Edwards Air Force Base, and F-22 SPO.]
Synthesis of distant signatures of underwater explosions for sea mammal hearing studies
Authors: Clark Joseph A. , Young Jane A.
Published: July 2002

Experiments which measure temporary threshold shifts (TTS) in marine mammals produced by loud noises provide one means for determining the effects that underwater explosions might have on sea life in the neighborhood of the explosion [S. Ridgway et al., J. Acoust. Soc. Am. 101, 3136(A) (1997)]. In order to obtain meaningful results which do not presuppose an understanding of the possible hearing damage mechanisms, the waveforms of the noises used as stimuli in the TTS measurements should reproduce the complexities of the actual sound field experienced by sea mammals at the outer edges of the region within which significant acoustic effects on hearing are expected. Multipath arrivals and significant refractive effects complicate the far-field signals produced by explosive shock tests. For example, a large number of superimposed short impulses are often observed. In this talk a system for synthesizing distant signatures of underwater explosions will be described. The computer-controlled system takes calculated pressure-time waveforms as input and generates an acoustic simulation of the input signal. Preliminary tests to validate the operation of the system will also be reported.
Acoustic geographic variation in two populations of Delphinus delphis
Authors: Toropova Caitlyn
Published: July 2002

Vocal patterns from two populations of common dolphin (Delphinus delphis) were compared. Field observations took place in the Channel Islands, CA and La Paz, Mexico. Whistles were recorded with a Sony HTI hydrophone (range=10–32 000 kHz) and schools were observed for group number and distance to the hydrophone by onboard observers. Sounds and spectrograms were analyzed for mean intensities in the (a) 15- to 20-kHz bandwidth, and (b) the ratio of the intensities from the 15- to 20-kHz band compared to the whole spectrum, 0–22 kHz. Significantly different (p<0.001) sound intensity levels were found between the La Paz and Channels Islands populations. When the 15- to 20-kHz band was examined, the values were 104.70±1.73 dB (mean ±S.E.) and 86.80 ±0.90 dB for the La Paz and Channel Islands, respectively. When the 15- to 20-kHz band was looked at as a function of the total energy in the 0 to 22-kHz band, significantly different energy levels were present as well (La Paz=76.2%, Channel Islands=67.9%). Therefore, the two populations were shown to be significantly different (p=0.001). This suggests that acoustic geographic variation is a useful tool for distinguishing populations within a species, and raises the possibility of external influences determining vocal patterns.
Is the echolocation ability of bottlenose dolphins too good?
Authors: Friedl William A.
Published: July 2002

Odontocete echolocation studies reveal a system with both great plasticity and precision, but knowledge of the animal’s day-to-day use of the process is limited. High-speed cine photographs of a trained bottlenose dolphin swimming underwater show that the dolphin’s head and rostrum move vertically even when the dolphin swims at modest speed. Does this movement limit or otherwise affect the echolocation precision of freely-swimming dolphins? Results from kinematic studies, combined with echolocation system descriptions from acoustic research, were examined to show if head movements might limit acoustic abilities of swimming dolphins. So far, these speculative approaches are inconclusive. The general synthesis, using disparate data from acoustic and kinematic studies, indicates that head motion associated with modest swimming speed does not degrade echolocation ability. Data from coordinated studies that involve both echolocation and movement at realistic, natural speeds are lacking. Given the difficulty involved in working with naturally swimming dolphins, this data set is likely to remain unfilled, so further conclusions will also remain speculative.
Statistical information for the development of computer models of jazz
Authors: Jarvinen Topi V.
Published: July 2002

Computer models of jazz improvisation have often been based on modelers’ personal musical experiences or on anecdotes about jazz musicians’ preferences. While this type of information is essential for any study of jazz, it would seem that it should be supplemented with some more concrete evidence on the underlying principles of jazz. This paper presents the results of a few recent statistical studies on bebop-styled jazz improvisation [e.g., T. Jarvinen, ‘‘Tonal Dynamics and Metrical Structures in Jazz Improvisation,’’ Dept. of Musicology, Univ. of Jyvaskyla, Finland]. In particular, it is discussed how bebop musicians employ meter, global tonality, and development of tonality in order to create coherent improvisations. It is argued that these types of results may help researchers design models with greater relevance and more explicit premises. An example of an application of these results is presented in another paper in this session by Petri Toiviainen.
Acoustic microcavitation at surfaces: New results in deinking of paper
Authors: Madanshetty Sameer I.
Published: July 2002

Deinking remains an important step in environmentally conscious manufacturing of paper. A novel method based on acoustic microcavitation is used for deinking xerographic ink from paper. Microcavitation evolves microimplosions, which are effective in causing deinking preferentially at ink sites. Acoustic microcavitation is brought about by low megahertz acoustic fields giving rise to micron-sized bubbles that live a few microseconds. In exposing a surface to continuous waves for a defined duration one could obtain cavitation effects in an average, overall sense; the details of nucleation, evolution of inertial events, and the precise interplay of field parameters in effecting cavitation, however, get glossed over. Studying pulsed cavitation using tone bursts at low duty cycles, instead of CW insonification, reveals interesting details of the initiation and evolution of acoustic microcavitation. Experiments indicate that the 2-D context of how a xerographic print is deinked might be useful in inferring some attributes of 3-D pulp deinking. Assuringly, the results indicate that paper fibers are entirely undamaged, and the ink separation leaves them immaculately white, and that acoustic methods for deinking are a viable, chemical free, environmentally responsible means of recycling paper.
Acoustic radiation force on micrometer-size particles: Size dependency and the efficiency of the superposition method
Authors: Yasuda Kenji
Published: July 2002

The acoustic radiation force on polystyrene spheres was measured through observation of the sphere movement in a 500-kHz ultrasonic standing wave. As predicted by Yosioka, the linear dependency of the force on the cube of the sphere radius began to fail when the sphere radius was below 5 μm. This failure can be accounted for by the presence of a shell layer that increased the effective radius of the sphere and it suggests that acoustic radiation might be used in handling microspheres smaller than previously thought [K. Yasuda and T. Kamakura, Appl. Phys. Lett. (in press)]. A method for concentrating particles using an acoustic radiation force by the superposition of the higher harmonics on fundamental ultrasound has also been investigated. The efficiency obtained when blood cells are concentrated by using the superposition method should theoretically be 20% better than that obtained when using the sine wave. Although the improvement obtained experimentally was only 5% because the waveform was incomplete, the potential usefulness of the superposition method has been demonstrated. [K. Yasuda, Jpn. J. Appl. Phys. 36, 3130–3135 (1997)].
Individual subjective preference of simulated sound fields by listeners for opera sound sources in relation to the subsequent reverberation time
Authors: Sakai Hiroyuki , Setoguchi Hiroshi , Ando Yoichi
Published: July 2002

The purpose of this study is to evaluate the subjective preference of a simulated sound field by listeners in changing subsequent reverberation time Tsub using vocal sources. A great deal of effort has been made in the study using music or speech [for example: Ando et al., Acustica 50, 134–141 (1982); Ando et al., J. Acoust. Soc. Jpn. 39, 89–95 (1983), in Japanese]. Subjective evaluation using vocal sources has never been examined, although vocal performance is often played in concert halls and opera houses. Subjective preference tests were conducted changing Tsub, which is one of the four objective parameters in relation to subjective preference of sound field. Individual differences of subjective preference as well as global preference are also considered.
Perceived unpleasantness of natural sounds: Ratio-scale measurement and psychoacoustic analysis
Authors: Ellermeier Wolfgang , Mader Markus , Daniel Peter
Published: July 2002

Paired comparisons of a heterogeneous set of ten natural sounds were collected from 60 listeners in order to determine: (1) if the sensation of unpleasantness is judged consistently across a wide range of acoustic stimuli; and (2) which sound features contribute to that sensation. The judgments conformed with the highly restrictive BTL model [R. D. Luce, Individual Choice Behavior (Wiley, New York, 1959)], thus justifying ratio-scale representation of perceived unpleasantness. The resulting scale values varied by a factor of 100 (diesel engine versus jackhammer). While they were not predicted by differences in A-weighted sound-pressure levels, a linear combination of the psychoacoustic attributes of loudness, roughness, and sharpness accounted for 98% of the variance in perceived unpleasantness.
Matched Doppler processing with multiple receivers
Authors: Searle Stephen J. , Gray Douglas A.
Published: July 2002

Matched Doppler processing (MDP) is a new technique that estimates the range and speed of a near-field narrow-band sound source as it moves past an underwater acoustic sensor by coherently matching the received signal against replicas. Replica vectors are generated according to a simple propagation model, which accounts for the effect of the Doppler phenomena on the signal phase. The data to be matched are the vector of complex outputs of Fourier transforms of contiguous blocks of hydrophone data and the matching is by means of a cost or correlation function, which processes the signal phase coherently. The main contribution reported is the extension of MDP to an array of receivers for localization of a source’s azimuth and heading as well as range and speed. Two methods are considered: The first method performs single receiver MDP on each sensor independently, then sums the cost values. The second method processes the signal phase coherently across space and also time. Extensive simulations compare the performance of both methods for an array of varying apertures and the number of receivers. Further simulation indicates that the second method affords sidelobe suppression, which improves performance when multiple signals are present. Application to tracking multiple sources is suggested and discussed.
On the use of signal autocorrelation matching in localization algorithms
Authors: Smith Kevin B. , Brune Joachim , Chiu Ching-Sang
Published: July 2002

Many new ‘‘robust’’ localization algorithms rely on the insensitivity of a high-order processor. In this work, the robustness of a simple, Bartlett-type processor based on matching broadband signal autocorrelation functions is investigated. Specifically, the autocorrelation of the time-domain signal and the autocorrelation of the frequency-domain response will be matched. In order to highlight weaker aspects of these quantities, logarithms of these functions will also be used. Measures of robustness to be examined include the size of the localization footprint on the ambiguity surface and the peak-to-sidelobe levels in the presence of environmental mismatch. A full-wave PE model is used to produce broadband replicas. Model-generated synthetic signals with complete knowledge of the environment will provide base-line results. [This work is supported by the Naval Undersea Warfare Center, Code 2121.]
Inverse noise rejection
Authors: Wilson James H. , Donald James E. , Nuttall Albert S.
Published: July 2002

Inverse beamforming (IBF) has been developed over the last decade by the authors, and has proved highly successful in numerous at-sea tests. IBF is a unique signal processing method because the noise field properties are first determined by inverse techniques as a function of frequency, azimuth, magnitude, and the ‘‘widths’’ of these three dependent variables. The statistical properties of the noise field are determined, and a beam-forming algorithm and six-dimensional tracker were developed to reject the noise and pass the signal (whose properties are well studied). IBF applies to deep water only, and this paper addresses the development of a similiar noise rejection algorithm in shallow water. The shallow-water problem is more complex due to the normal mode propagation characteristics at low frequencies, and the diversity of noise mechanisms in shallow water. Noise measurements are critically needed in shallow water to validate this approach.
An autonomous acoustic recorder for shallow arctic waters
Authors: Greene Charles R.
Published: July 2002

Autonomous acoustic recorders permit full-time environmental monitoring for extended periods. The device described here has been used on the ocean bottom in depths to 44 m. It uses a 4-Gbyte disk to record sounds sampled continuously at 1 kHz (500-Hz bandwidth) except that for 1 min every 14 m 24 s the sample rate is doubled. The lower sample rate is for monitoring the sounds of seismic surveys (airgun pulses) and bowhead whale calls. The higher sample rate is for ambient noise analysis. Capacity is adequate for 24 days. Retrieval is by grappling and has been used on 100 units that operated for 15 days in the Alaskan Beaufort Sea during September 1996. [Work supported by BP Exploration (Alaska), Inc.]
Acoustical considerations in developing the educational exhibition Mostly Music
Authors: Taylor David
Published: July 2002

Mostly Music is a new exhibition designed and developed by the Pacific Science Center. It will visit nine museums around North America during its 3-year tour. Developing an exhibition on the science and technology of music and musical instruments required consideration of varying background sound levels depending on the number of visitors in the exhibition, cross-talk between exhibits, requirements of sound fidelity and sound isolation, and sound reinforcement in some instances. Design case study will be presented along with anecdotal comments on planned versus actual results on individual exhibits.
Calibrations of low level sound calibrators
Authors: Wu Lixue , Wong George S. K.
Published: July 2002

Sound calibrators are designed to generate known sound-pressure levels at specified frequencies. Performances of calibrators are usually verified by accredited acoustical test laboratories. According to the latest standard revision [IEC 60942, Ed. 2, Sound Calibrator], the level of ambient noise reaching the microphone during testing of the calibrator shall be at least 30 dB lower than the measured sound-pressure level for classes 0 and 1 calibrators, and at least 25 dB lower than the measured sound-pressure level for class 2 calibrators. For calibrators, high-ambient noise will affect the uncertainty of the measurement, and this is particularly severe when the calibrator is operating at a relatively low sound-pressure level, such as 74 dB. In this paper, methods to reduce the effect of ambient noise on calibrators are presented. The uncertainties of the measurement associated with the methods are estimated. The measured sound-pressure levels based on the new methods are compared with those measured in an anechoic chamber using the traditional method.
Measurements of personal aircraft noise exposure of outdoor recreationists
Authors: Sneddon Matthew , Fidell Sanford , Pearsons Karl
Published: July 2002

The at-ear noise exposure of hikers created by sporadic aircraft overflights in an outdoor recreational setting was measured on public lands underlying an active military operations area. Cumulative noise levels for entire hikes and for shorter time intervals were compared with conventional (place-oriented) noise monitoring records. Variability in personal aircraft noise exposure, even of hikers on the same itinerary but at different times of day, was so great as to call into question the adequacy of conventional noise exposure measurement and aircraft noise exposure modeling as representations of the actual aircraft noise experience of outdoor recreationists. Distributions of closest points of approach of aircraft to hikers (derived from radar flight track information and time-stamped geo-coding of hikers’ paths) were examined as an explanatory mechanism for the variability. [Work supported by U.S. Air Force Air Combat Command.]
Nighttime sleep disturbance in residential communities—A review of recent U.S. field research and a recommended new dose–response relationship
Authors: Finegold Lawrence S.
Published: July 2002

This paper provides a brief review of field research on nighttime sleep disturbance in residential communities which has been conducted in the United States over nearly the past decade. It compares the research methodology for studying sleep disturbance that has evolved during this series of research projects with the research approaches predominantly used in Europe. The focus is on transportation noise sources, primarily aircraft noise. It also offers a new dose–response relationship based primarily on the U.S. field data collected around civilian airports and military airbases. The new sleep disturbance prediction curve is recommended as an update to the interim curve adopted by the Federal Interagency Committee on Noise (FICON) in 1992. At that time, there was a lack of consensus concerning whether both laboratory and field research data should be used in the development of a new prediction curve. Thus the FICON curve combined the major field and laboratory data published in the U.S. up to that time in an admittedly interim curve. The currently proposed new prediction curve uses only data from field studies and incorporates some of the European research data.
Comparison of noise metrics for predicting the annoyance of aircraft overflight noise
Authors: Pearsons Karl , Howe Richard , Sneddon Matthew , Silvati Laura , Fidell Sanford
Published: July 2002

Two groups of 30 audiometrically screened test participants judged the relative annoyance of two comparison (variable level) signals and 30–34 standard (fixed level) signals in an adaptive paired comparison psychoacoustic study. The signal ensemble included primarily stage II and stage III aircraft overflights, as well as synthesized aircraft noise signatures. Test signals were presented for judgment as heard indoors (test 1) and outdoors (test 2), in the presence of continuous background noise, under free-field listening conditions in an anechoic chamber. For both tests, analyses of the performance of 30 noise metrics as predictors of these annoyance judgments confirmed that the more complex metrics were generally more accurate and precise predictors than the simpler methods. EPNL was slightly less accurate and precise as a predictor of the annoyance judgments than a duration-adjusted variant of Zwicker’s loudness level. [Research was supported by NASA, Langley Research Center, Hampton, Virginia.]