bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic propagation in a lapse temperature gradient
Authors: Van Moorhem William K.
Published: October 2005

The propagation of acoustic waves in the atmosphere with a realistic lapse temperature gradient has been modeled analytically. The atmosphere is assumed to be bounded by a ground surface described by a finite normal impedance. Two cases will be discussed: the plane wave solution, where plane waves are assumed to originate at infinite heights above the ground; and the point source solution. In both cases numerical evaluation of the solution has been carried out. The solution yields the unexpected result of weak refracted waves. [Work supported by NASA Langley.]
On the perception of intonation from sinusoidal signals: Tone height and contour
Authors: Remez Robert E. , Rubin Philip E.
Published: October 2005

Our recent investigations of intonation have employed signals that consist of three or four time-varying sinusoids. Each tone reproduces the changes in formant center frequencies from a natural utterance. Such sentences produce a clear impression of intonation though there is no fundamental frequency common to the sinusoids composing the pattern. We find that the tone corresponding to the first formant is the basis for sinusoidal intonation, much as signal periodicity in the region of the first formant (not coincidentally, the dominance region) provides the information for pitch in natural speech. A series of differential similarity tests was used to determine whether listeners represent sinusoidal intonation as patterns of specific tone heights or as patterns of relative pitch changes. The results are discussed in terms of auditory frequency coding of the speech signal, intonation, whispered speech, and musical pitch. [Supported by the National Institute of Child Health and Human Development.]
Effect of turbulent boundary layer flow on measurement of acoustic pressure and intensity
Authors: Lauchle Gerald C.
Published: October 2005

Acoustic measurements performed with pressure sensors (microphones and hydrophones) can be subject to error if the sensors are in contact with a turbulent boundary layer flow. These errors are a result of the random pressure fields (flow noise) generated by the turbulent motions of the fluid. In this paper, a simple analysis is given whereby the flow noise response of a pressure sensor placed in a turbulent boundary layer flow can be estimated. If the purpose of the sensor is to measure the sound emitted from a source outside of the turbulent boundary layer, then a bias error for the measurement can be calculated. The error formula is equally applicable to intensity measurements made with the two-sensor technique, providing the mean flow Mach number is small. Example calculations are presented. [Work supported by NAVSEA 63R-31.]
Cell biology effects of ultrasound and microwave hyperthermia
Authors: Corry Peter M.
Published: October 2005

Hyperthermia, or elevated temperature in the 41 °C to 50 °C range, in cancer treatment has been the subject of intense renewed interest over the past decade. This interest has come about primarily for three reasons: (1) conventional therapies such as ionizing radiation and chemotherapy have failed in several disease categories, (2) historical anecdotal reports of tumor responses after episodes of fever, and (3) the development of instrumentation systems for the controlled and reproducible administration of tumor temperature elevation such as ultrasound and microwaves. Until recently it was thought that cancer cells possessed an intrinsic sensitivity to these elevated temperatures, however, application of the ever more sophisticated techniques of modern cellular and molecular biology have demonstrated that solid tumor physiological factors, such as a lowered pH and nutrient deprivation appear to be the responsible factors rather than the transformation to malignancy. Other studies have demonstrated that hyperthermia can also result in dramatic enhancement of the more conventional therapies in addition to the heat-induced cytotoxicity. This latter enhancement comes about by the alteration of membrane permeabilities and the inhibition of subcellular repair mechanisms and in some cases, both effects. These observations have led to several studies to develop possible advantages of the various methods of tumor temperature elevation, however no specific effects of either ultrasound or microwaves have been documented other than those attributed to the elevation of tissue temperatures. [Supported in part by CA-17891 and CM-17524 from the NCI.]
Anchor line theory of fundamental frequency variation in speech
Authors: Landahl Karen L. , Lieberman Philip
Published: October 2005

We propose a theory that appears to characterize quantitatively those aspects of the temporal pattern of fundamental frequency (F0) variation that delimits the constituent structure of speech, most notably sentences. The anchor line frequency theory we propose provides a major refinement of the breath-group theory [P. Lieberman, Intonation, Perception and Language (MIT Press, Cambridge, MA, 1967); J. E. Atkinson, J. Acoust. Soc. Am. 63, 211–222 (1978)]. We will present an analysis of data that is consistent with the hypothesis that the F0 contour (1) provides continuity across voiced-unvoiced segmental boundaries, (2) that local F0 minima tend to fall on anchor lines, (3) that the anchor lines are linear level, falling, or rising, and (4) that the level anchor is most characteristic for normal, nonemphatic declarative sentences of American English and English. We further propose that the F0 continuity inherent in the anchor lines may play a crucial function in the perception of speech by “tagging” a speaker's voice so that we may track it in an environment of noise and competing voices.
Stop voicing, intonation, and the F contour
Authors: Abramson Arthur S. , Lisker Leigh
Published: October 2005

The F0 contour of an utterance is likely to show perturbations correlated with the voicing states of syllable-initial consonants. Thus the F0 after the release of a voiceless stop will be higher than after a voiced stop. Research has shown that such differences can play a minor perceptual role in voicing distinctions. This phenomenon has also figured in arguments about the rise of phonemic tones in certain language families. We are concerned here with how the robustness of the feature might be affected by sharply contrasting intonations and the presence of a voicing break in the preceding carrier. We composed pairs of sentences with the words bark and park preceded by [s] in one pair and a vowel in the other. Three native speakers of American English recorded them ten times each, with a rising intonation and a falling intonation. Data are presented to show the extent to which the effect persists across the several contextual conditions, and inferences are drawn as to its availability for a role in speech communication. [Work supported by NICHD.]
Prosodic rules for speech synthesis from Japanese text
Authors: Sagisaka Yoshinori , Sato Hirokazu
Published: October 2005

Three prosodic rules are proposed to realize Japanese text-to-speech conversion system. The first prosodic rule groups words into accent phrases and breath groups, using both the grammatical relationship among adjacent words or phrases by local dependency analysis and the restriction of breath group length. The second prosodic rule decides the accent position in each accent phrase, using accent attributes of constituent words. Accentuation rules are applied to constituent words in an accent phrase according to its structure. These two kinds of information, accent (or breath) group boundaries and accent positions, are utilized to generate a sentence fundamental frequency pattern. The third segmental duration control rule decides segment temporal patterns, which are used to lengthen or to shorten prestored syllabic multiphone units such as CVC and CV segments. These prosodic rules enable one to produce speech waveform with natural prosody using ECL's speech synthesis system.
Physical acoustic information for magnitude estimation of rate of speech
Authors: Kluender Keith R.
Published: October 2005

Several studies have demonstrated that the phonetic identity of a segment can be altered by the rate of a precursive sequence. While this rate normalization effect has been shown for both consonants and vowels [J. L. Miller, Phonetica 38, 159–180(1981)] it has never been clear what the physical acoustic basis of the rate information is. In these experiments, subjects' magnitude estimations of rate for a short passage are used to assess the physical acoustic parameters used by the listener to perceive rate of speech. From earlier experiments [F. Grosjean and N. Lass, Lang. Speech 20(3), 198–208(1977)] it appears likely that the source of information for rate is not based upon any higher information including words or word boundaries. In the first experiment, subjects give rate estimations for a passage, spoken at five rates by a female English speaker that has been low-pass filtered at 300 Hz. Estimates for these filtered stimuli, in which energy for F1 and higher formants is deleted leaving only pitch and amplitude information, are indistinguishable from those for intact passages. It appears then that not even phonetic, perception is necessary for perception of rate in this paradigm. Data for estimates of rate for passages with only pitch or only amplitude information will also be presented. [Work supported by NINCDS.]
Temporal speech characteristics and vocal pleasantness in the aging voice
Authors: Oyer Herbert J. , Trudeau Michael D.
Published: October 2005

Previous work by the authors emphasized temporal characteristics of speech as critical cues in age estimation. The present study assessed the role of the same temporal cues in listener perception of vocal pleasantness (PL). Twenty-four speakers (12 male), ages 41–82 years, read the passage “My Grandfather” and prolonged /aeiou/. With the first two sentences of “My Grandfather” as the stimulus, 22 college-age naive listeners (11 male) judged speaker PL on a five point scale. The times to initiate and to terminate /aeiou/, the time to articulate /maɪ gnændfðɚ/, reading rate, pause time within the passage, and speaker sex were regressed against PL. The single best predictor for PL was reading rate (R-square = 0.48) and the best significant model (12 variables) for PL yielded R-square = 0.77. Similar to age estimation, the perception of PL appeared to be strongly influenced by temporal characteristics of speech. While the contributions of individual variables differ, the results suggest that estimations of age and pleasantness involve closely related perceptual processes.
Physical parameters of Chinese and Australian woods in relation to their use in violin making
Authors: Hutchins Morton A.
Published: October 2005

Report covers strip tests showing physical parameters of native woods from China and Australia used in construction of string instruments of the violin family or considered of potential use in such instruments. Results are compared with those obtained on European and American woods conventionally used in violin making.
A method employing OR-ing for treating dynamic signals
Authors: Struzinski William A.
Published: October 2005

In a previous study [W. A. Struzinski, IEEE Trans. Acoust. Speech Signal Process. ASSP-31, 651–656 (1983)], OR-ing loss data were provided for a system composed of electrical integrators followed by an OR-ing device and a display. This analysis was for static signals. In this paper, consideration is given to a sinusoidal frequency modulation signal. For this type of signal, we examine an alternative processor where this is no pre-OR-ing device. The performance of the alternative processor is evaluated and compared with the previously analyzed system. An experimental performance comparison of the two processors was also conducted on the NUSC Acoustic Display Research Facility. Based upon the results of the subject analysis, it is concluded that for a sinusoidal frequency modulation signal, there should be no electrical integration prior to OR-ing.[Work supported by NAVSEA.]
Signal detection for mixed multichannels
Authors: Ma Kai-Kuang , Nolte L. W.
Published: October 2005

In this paper the detection performance is presented for a signal received over M different channels. Two situations are considered; (1) the signal has uncertain parameters, and (2) the channels have a mixture of uncertainties, such as stable and rapidly varying phase channel types. This can occur in the ocean where the propagation characteristics are such that one channel may be quite stable over long periods of time and another may not. The effects of channel uncertainties on optimum performance are presented on the ROC. The sensitivity to knowledge of the channel types is also discussed. [Sponsored by ONR Code 411SP.]
Profile information improves Weber fraction
Authors: Green David M. , Mason Christine R.
Published: October 2005

We measured the ability of observers to detect an increment in the intensity of a 100-ms 1000-Hz sinusoid under two conditions. In the first condition, the observer heard single 1000-Hz sinusoids —either the standard or the standard plus the increment. In the second condition, ten other sinusoids were added to the 1000-Hz sinusoid with frequencies ranging from 200 to 5000 Hz. These additional components were equal in intensity to the standard and the frequency ratio between successive components of the 11-component complex was 1.38. The basic task for each condition was the same, to detect an increment in the 1000-Hz component. The increment was easier to detect in the complex spectrum or “profile,” presumably because the additional components allow one to make simultaneous comparisons among the different components. Only a successive comparison between the 1000-Hz components was possible in the single sinusoid condition. The improvement is as much as 10 dB for some observers and conditions, when expressed in terms of the signal relative to the standard. [Work supported by NIH.]
Perceived magnitude of two-tone-noise complexes
Authors: Hellman Rhona P.
Published: October 2005

Overall perceived magnitude (loudness, annoyance, and noisiness) of estimation. The stimuli were tone pairs added to a low-pass noise that was attenuated by 5 dB/oct above 600 Hz. The low-frequency tonal component remained at 250 Hz, while the high-frequency component was set, in separate sessions, at 275, 350, 500, 1000, and 3000 Hz. Listening was binaural through earphones. Within a session, the experimental variables consisted of the SPLs of the added tones, the SPL of the noise, and the tone-to-noise ratios relative to the appropriate 1/3-octave-band pressure levels. Data analysis showed that perceived magnitude is a complex function of the overall SPL of the noise-tone-complex, the frequency separation (ΔF) between the tonal components, and tone-to-noise ratio. The results are related to underlying mechanisms governing loudness and masking. The possible role played by consonance and dissonance effects described by Plomp and Levelt [J. Acoust. Soc. Am. 38, 548–560 (1965)] is also discussed. [Work supported by NASA Langley Research Center.]
Comparative redundancy as an influence on loudness
Authors: Weiler Ernest M. , Sandman David , Cobb Frederick , Davis James M.
Published: October 2005

Adaptation to a stimulus environment often implies suppression of the redundant features in favor of stimuli carrying more information. Study of auditory adaptation of a continuing (redundant) stimulus, also requires consideration of the less redundant “comparison” stimulus. A magnitude estimation loudness adaptation study (1 kHz, 60 dB) designed to parallel the steps of the SDLB technique, yielded the following: (a) no loudness adaptation occurred during the pre-test baseline when binaural simultaneously intermittent stimuli were presented, (b) immediately afterward, 7 min. of continuous redundant monaural stimulation yielded negatively accelerated adaptation, (c) finally, restoration of intermittent stimulation in the contralateral ear, resulted in apparent binurally “induced” adaptation of the continuous tone, but not of the less redundant intermittent tone. Previously, monaural heterophonic balances (Weiler and Friedman, 1973, etc.) resulted in the decline of the continuous (redundant) tone in the presence of an intermittent comparison tone. In summary, adaptation occurs in the more redundant stimulus when the two are competitive, similar, and in the same frame of reference.
Compensating for the hall
Authors: Zaret Peter
Published: October 2005

The performer and conductor must adjust their performance to compensate for the characteristics of the concert hall. A very different style of playing is required for an acoustically damped recording studio as compared with a live concert hall. In each ease, the tonal balance must be adjusted by the performers because what they hear differs from that heard by the audience. The difference is a strong function of the hall or studio acoustics.
The exchange rate and noise-induced hearing loss
Authors: Suter Alice H.
Published: October 2005

Scientists and policy makers have debated the subject of the exchange rate (3, 4, or 5 dB per doubling or halving of duration) for many years. A recent historical review of this topic in the U.S. reveals that early criteria were based on temporary threshold shift (TTS) studies, and it is well known that TTS is not always a valid predictor of permanent hearing impairment. OSHA's 5-dB exchange rate is founded on TTS experiments and therefore is of dubious validity. Data from experiments of noise-induced cochlear damage support the use of the 3-dB exchange rate for single exposures within an 8-h day. There is some evidence that intermittency can be beneficial, at least in the laboratory, which may support a correction to the daily “dose” as calculated by the 3-dB rule. Data from most field studies support the 3-dB exchange rate, with the exception of some (but not all) studies of hearing loss due to intermittent noise in outdoor occupations. Because any adjustment to the daily, average exposure level for outdoor occupations will be fraught with complication, a more satisfactory and protective approach is simply to use the 3-dB exchange rate for all conditions.
Radiation forces between small particles in a sound field
Authors: Nyborg Wesley L.
Published: October 2005

When ultrasound propagates through an aqueous suspension of particles, radiation forces exist between neighboring particles. This is a phenomenon of biophysical interest because, in suspensions of biological cells, it leads to aggregation of the cells into lines or sheets under some conditions. Considering a pair of identical spherical particles whose separation distance r is small, it is found that the interaction force can be expressed as −∇ W, where W is a scalar function, which may be called the “acoustic interaction energy” for the pair. This energy is proportional to r−3 and to (3 cos2 φ − 1), where φ is the angle between the line of centers and the line along which motion occurs in the local ambient sound field. Also W is proportion to a6u20, where u0 is the acoustic velocity amplitude and a is the particle radius. A criterion for aggregation can be arrived at by setting a characteristic value of W equal to the thermal energy kT, as was done by Schwan in treating pearl-chain formation by electromagnetic waves. [Supported by NIH grant GM-08209.]
Survey of high-frequency bottom reverberation
Authors: Goldsberry T. G.
Published: October 2005

High-frequency sonars are almost always reverberation limited and the most important contributor to this reverberation is backscattered energy from the ocean bottom. This has been long recognized; however, until recently the status of knowledge about this important subject was reflected in the classic paper of McKinney and Anderson [J. Acoust. Soc. Am. 36, 158–163 0964)]. In recent years there has been a revival of interest in acoustic scattering from the ocean bottom at high frequencies, including measurements at sites on the East, West, and Gulf coasts. This paper presents a survey of recent and historical work in the area.
Environmental bottom characterization required for modeling and prediction of high-frequency acoustic bottomscattering
Authors: Richardson Michael D.
Published: October 2005

Modeling and prediction of acoustic bottom scattering require characterization of sediment geoacoustic and bottom roughness properties. Data, from five recent shallow-water acoustic experiments, are presented on the temporal and spatial variability of values of those bottom parameters thought to be important to bottomscattering. The importance of hydrodynamic and biological processes in controlling relevant sediment geoacoustic and roughness properties is also discussed. An improved understanding of which physical scattering processes dominate bottom scattering at different frequencies, beamwidths, pulse lengths, and grazing angles is required to predict bottomscattering from environmental properties. [Work supported by NORDA.]
Acoustic wave scattering by 3-D finite axisymmetric shells in water
Authors: Baskar S. , Varadan Vasundara V. , Varadan Vijay K.
Published: October 2005

In this paper, the scattering of acoustic waves by 3-D finite axisymmetric shells immersed in a fluid is analyzed. The governing equations for axisymmetric shells are derived by including the effects of rotary inertia terms and the dynamic impedance of the shell is then evaluated numerically and incorporated into the T-matrix formalism. Using the T matrix thus computed the farfield scattering is evaluated. Numerical results will be presented for the backscattered amplitude as a function of frequency for a finite cylindrical shell with hemi-spherical endcaps for different angles of incidence. This new semi-analytical method will be compared with the finite element method for incidence along the axis of the shell.
Image reconstructions from the applications of the ramp response signatures
Authors: Tsao S. J. , Varadan Vijay K. , Varadan Vasundara V.
Published: October 2005

The ramp response signatures have been shown to relate well to the profile functions of various objects in the acoustic, electromagnetic, and elastic scattering problem. A modified method to reconstruct the scatterer image using the ramp responses at a finite number of look angles is introduced in this paper. The idea of synthetic scatterer image generation comes from a 3-D “approximate limiting surface” which has been well applied by Moffatt and Young in the image processing of perfectly conducting scatterers. The difficulty in getting good ramp responses by using the analytical frequency spectrum is resolved by modifying the T-matrix method to a wider bandwidth. The generated images of spherical, and oblate and prolate spheroidal voids in elastic solids, and those of rigid scatterers immersed in an acoustic field are presented. Some images of various shapes of scatterers in 2-D problems are also shown. Finally, an attempt to get the image of an elastic body and/or shell in an acoustic medium is discussed.
Presentation-order effects in the discrimination of rapidly presented short intervals
Authors: Fleet Gregory J. , Shelton Brian R.
Published: October 2005

We previously reported a forward masking effect in a duration discrimination task [G. J. Fleet and B. R. Shelton, J. Acoust. Soc. Am. Suppl. 1 74, S10 (1983)], suggesting that the restriction of performance in the discrimination of rapidly presented brief durations was peripheral. This would predict a presentation-order effect, where a long-short discrimination would be easier than short-long. Two experiments examined this idea. The first study was two-interval forced-choice paradigm, with the thresholds for the long-short and short-long presentations adapted separately. A second experiment examined these same discriminations in a same-different paradigm. Signals were 80-dB SPL noise bursts fast gated in a continuous 60-dB noise background. Base durations of 25, 50, 100, and 200 ms were used, with ISI values of 25, 50, 100, 200, 400, 800, and 1600 ms. Counter to expectations, thresholds were much lower for the short-long presentations. These data are discussed in terms of their relation to the proposed peripheral limitation thesis, as well as the arguments that this presentation-order effect is the result of perceptual or assimilation effects. [Work supported by NSERC.]
Resonant frequencies and modes of ribbed cylindrical shells
Authors: Burroughs Courtney B. , Hayek Sabih I.
Published: October 2005

Measured data on resonant frequencies and modes of a ribbed cylindrical shell in air and immersed in water are presented. The ends of the shell are closed with caps so that the interior remains dry during immersion. An outer thin shell is added and resonant frequency and mode measurements repeated for the concentric shells in air and in water. The two shells are structurally coupled via annular plates between the two concentric shells. The volume between the shells is water-filled. The effects of the water-loading and the concentric outer shell on the resonant frequencies are discussed. Results from analytic models are used to assist in interpretation of the measured data.
Hermite-Baranek representation of acoustical transfer function
Authors: Lyon Richard H.
Published: October 2005

The advent of digital processing of acoustical (vibration and sound) transmission data has diminished interest generally in functionably based methods of system representation. Nonetheless, such methods continue to have a place because they offer certain economies when only a few terms of the expansion are able to represent the system and because they may provide physical models for the system under study. The Laguerre representation is an example which provides both a set of orthogonal functions for expansion of time domain behavior and a set of physical systems for modeling at the same time. Unfortunately, Laguerre expansions are inappropriate for the modeling of continuous systems with large numbers of degrees of freedom. A more appropriate expansion in this case is in Hermite (or Hermite/Gaussian) functions. When these functions are used to represent causal or minimum phase systems, it may also be useful to expand a part of the transfer function in Beranek functions which are Hilbert transform of the Hermite function. Beranek functions have orthogonality and recursion relations very similar to the Hermite functions. An example of the use of these expansions is presented.
Automatic alignment of phonetic transcriptions with continuous speech
Authors: Zue Victor W. , Leung Hong C.
Published: October 2005

The alignment of a speech signal with its corresponding phonetic transcription is an essential process in speech research, since the time-aligned transcription provides direct access to specific phonetic events in the signal. Traditionally, the alignment is done manually by a trained acoustic phonetician. The task, however, is prone to error and is extremely time consuming. This paper describes a system that performs the time alignment automatically. The alignment is achieved using a standard pattern classifiction algorithm and a dynamic programming algorithm, augmented with acoustic-phonetic constraints. The speech signal is first segmented into six broad phoentic classes using a sequence of nonparametric pattern classifiers arranged in a binary decision tree. The output of this initial classification is then aligned with the transcription using a knowledge-based dynamic programming algorithm. The aligned broad class segments provide “islands of reliability” for more detailed segmentation and refinement of boundries. Acoustic-phonetic knowledge is utilized extensively in the system during feature extraction for pattern classification, specification of constraints for path searching in dynamic programming, and subsequent knowledge-based segmentation labeling. The system was evaluated on sixty sentences spoken by three speakers, two male and one female. Aproximately 93% of the segments were mapped into only one phoneme. Over 70% of the boundaries found by the automatic system were within 10 ms of those determined manually by an acoustic phonetician. [Work supported by the Office of Naval Research under contract N00014-82-K-0727 and by the System Development Foundation.]
Some techniques for controlling distinctive contours of speech parameters in experimental manipulation
Authors: Graff David , Seitz Franz
Published: October 2005

All acoustical properties which contribute to signaling phonemic contrasts are, to some extent, “time-varying.” However, some properties, e.g., formant trajectories in diphthongs and fundamental frequency trajectories in tones, rely for their distinctiveness on time-varying contours which are quite complex. These complex contours are composites of two or more parameters, e.g., duration, rate of change, and relative values of extrema. Experiments concerned with the contribution of particular aspects of the contours' patterns to the perception of phoneme categories face the following problem: How are such composites of parameters to be controlled and modified to produce a synthetic continuum of variants for the basic ceteris paribus experimental paradigm? This report presents some techniques that we have devised which address this problem, and evaluates their effectiveness in LPC and terminal analog synthesis. The contours of formant trajectories in varieties of English, and the contours of fundamental frequency trajectories in Vietnamese tones, have been systematically modified using these techniques in order to produce stimulus sets. The central problems were time-warping and interpolating smooth curves through data points.
The Delta System for synthesis rules
Authors: Hertz Susan R. , Kadin James , Karplus Kevin
Published: October 2005

The Delta System is a computer system for developing synthesis rules. Building on nine years of experience with Hertz's SRS synthesis system [J. Acoust. Soc. Am. 72, 1155 (1982)], it gives users more flexible rule-development facilities and enables them to produce considerably more practical rules. The Delta System provides a high-level structured pattern matching language called Delta. The system achieves compact, efficient, and portable rule sets by compiling rules from Delta into a pseudo-machine language. With Delta, rule-writers can easily define and manipulate a broad class of utterance representations, ranging from linear strings to multi-level structures. An utterance consists of multiple synchronized steams of user-defined symbols and associated attributes. The symbols can represent phrases, words, morphs, demisyllables, phonemes, subphonemic units, etc. Delta's control structures and sophisticated pattern matching ease the writing of efficient rule sets. Symbols and attributes from all levels can be freely mixed in the patterns to be matched. When completed, the Delta System will accomodate almost any synthesis scheme, will support rule development for any language, will be extremely portable, and will produce compact, efficient rule sets.
Evaluating LPC-coder performance using voice quality analysis
Authors: Hanson R. J. , Laver J.
Published: October 2005

A system for characterizing individual voice quality has been developed and used successfully to describe normal voice, pathological voice, and paralinguistic affect. In this study, voice quality analysis is used to evaluate the distortion introduced by LPC-based speech coding. Vocal profiles of speakers are obtained by having trained judges rate the extent to which 21 phonetically based features deviate from the “neutral” setting. Profiles for original and coded material from the same speaker are compared and a distortion measure is derived that quantifies the change in voice quality attributable to the coder. Results indicate that voice quality analysis is sensitive to many characteristics of LPC types of source coding, quantization of spectral parameters, and pole frequency and bandwidth accuracy.
Low-frequency ambient noise mechanisms: A comparison of open-ocean and under-ice data
Authors: Browning D. G. , DiNapoli F. R. , Nielsen R. J. , Fisch N. P. , Mellen R. H.
Published: October 2005

A large increase in ambient noise spectrum level is observed in the open ocean at low frequencies. Most investigators have suggested wind and wave reduced (surface coupled) mechanisms. [Kibblewhite et al., J. Acoust. Soc. Am. Suppl. 1 74, S121 (1983)]. Our analysis of recent under-ice ambient noise data shows no large increase at low frequencies thus indirectly supporting the hypothesis of a surface coupled mechanism in the open ocean. The general level and frequency dependence of the spectrum suggests, however, the existence of a locally generated noise threshold which may be due to internal waves or seismic activity. [Work is funded by ONR Code 425-AR.]
The role of F1 cutback in the perception of voicing contrasts
Authors: Pastore Richard E. , Szczesiul Rosemary , Nowikas Karen , Logan Robert
Published: October 2005

Recent research has convinced us that limitations on temporal order judgments (TOJ) do not provide an adequate acoustic basis for voicing contrast. Our correct research focuses on F1 cutback, a second major cue in voicing contrasts. F1 cutback exhibits categorical perception and at least some of the parameter dependencies found for voicing contrasts, but not found with TOJ. These results will be described. The possibility that F1 cutback, acting alone or in conjunction with temporal order cues, may serve as a major acoustic cue for contrasts will be discussed.
Stop CV duration and dichotic temporal order judgment
Authors: Rafferty E. , Hughes L. F. , Miller C. J.
Published: October 2005

At a previous meeting of the Society we presented data which showed that sensitivity for dichotic temporal order judgment decreased with increases in intensity disparity between channels. Further work indicated that overall presentation level (whether 50 or 66 dB) did not affect performance as long as both channels were of equal intensity. In this study we varied the duration (40, 60, 90, and 180 ms) of naturally produced stop CVs having stimulus onset asynchronies of 2, 4, 8, 16, 32, and 64 ms. Seven subjects indicated the ear stimulated first. The difference between normal deviates for hits and false alarms was measured. Results contrasted with data from studies using monaural or binaural presentation in that sensitivity increased with increasing stimulus duration. In addition, plots of each duration condition revealed performance to be a monotonic function of stimulus onset asynchrony. Further testing on two subjects showed that at higher intensities the decrement in performance for 40-ms stimuli was attenuated. Results are discussed in terms of duration-intensity tradeoffs in dichotic temporal order judgment.
Vibration signature analysis in power plants
Authors: Ying S. P.
Published: October 2005

In order to reduce noise and vibration levels in power plants, vibration signature analysis was utilized as a diagnostic technique. Accelerometers, strain gauges, pressure transducers, or a combination thereof were used to monitor the vibration signatures and pressure pulsations. The signals from the sensors were analyzed by using a dual channel fast Fourier transform (FFT) analyzer to obtain cross-correlation functions in time domain and coherence functions in frequency domain. These techniques can pinpoint the source of vibration and have been successfully applied to turbine-generators, pumps, and fans in power plants to prevent trip-out and fatigue damage. Vibration signature interpretations for rotating machinery, cracked components, and structural resonant vibration are discussed for several case histories. Recommendations which have been implemented for the elimination of excessive vibration problems are also presented.
A model for wing vibration excited by a propeller wake
Authors: Martinez Rudolph
Published: October 2005

Predictions are made of unsteady airloads induced on a wing by the near wake of an upstream propeller. The forced infinite-beam equation is then solved and levels of structureborne sound at the cabin position obtained. The propeller wake is modeled as a system of infinite, straight vortices in rotary motion cutting through the wing at the two sparwise positions given by y = ± R, where R denotes the propeller radius. The vortex arrangement is assumed rigid and therefore unaffected by the presence of the solid surface, or by mutual induced motions. Velocities induced on the wing plane yield time and spanwise variations of the effective angle of attack, from which the unsteady running lift driving the wing structure is computed using locally two-dimensional, quasisteady aerodynamics.
Asymptotic modal analysis and statistical energy analysis of dynamical systems
Authors: Dowell Earl H.
Published: October 2005

The well known text by Lyon on Statistical Energy Analysis (SEA) [R. H. Lyon, Statistical Energy Analysis of Dynamical Systems: Theory and Applications (MIT Press, Cambridge, MA, 1975)] is the standard reference on the subject. As originally conceived SEA was based upon several plausible hypotheses. Various authors have considered the underlying basis for SEA and thereby advanced our understanding of it. In the present paper, the relationship between classical modal analysis (CMA) and SEA is studied. It is shown how the results of SEA may be obtained as an asymptotic limit of CMA. The present work only considers the response of a single general linear structure under a random or sinusoidal load. However future plans will consider (a) the structural acoustic response of an enclosure bounded by a flexible wall and excited by external forces and (b) two (or more) coupled structural systems. Here the emphasis is on (1) a new derivation of the SEA results from CMA for a single structure under a random load, (2) the generalization of the usual SEA result to show that, asymptotically, all points on the structure have the same response. In the literature this is sometimes invoked as an assumption. Here the result is derived as part of the asymptotic limit of CMA. (3) A numeriCal example which displays the manner in which the asymptotic limit is approached for random loading and (4) an extension of the usual SEA result for sinusoidal loading. In view of the above, the present results might be called more appropriately Asymptotic Modal Analysis (AMA) rather than SEA.
Effect of neonatal conductive hearing loss on neuronal size in the ventral cochlear nucleus of guinea pigs
Authors: O'Connell Nancy A.
Published: October 2005

The left ear of newborn guinea pigs was closed by removing the skin and cartilage of the external auditory meatus and pulling the surrounding tissue over the opening with silk sutures. At 60 days of age the animals were anesthetized with chloral hydrate and auditory brainstem responses (ABR) were measured before and after destroying the intact right ear. After ABR testing the animals were killed and their cochleas were examined histologically. Right and left brainstems were embedded in paraffin, serially sectioned and stained with cresyl violet. The cross-sectional area of four different cell types was measured, using a total of 210 cells of each type from each side. For all four groups; large spherical cells, small spherical cells, pale globular cells, and octopus cells, soma size was significantly smaller (P < 0.01) on the left side. This result for guinea pigs, a precocial animal, agrees with earlier findings for an altrical animal the mouse [D. B. Webster, Exp. Neurol. 79, 130–140 (1983)]. [Supported by NIH training grant NSD-07058 and the Louisiana Lions Eye Foundation.] Present address: Dept. of Biological Sciences, Loyola University, New Orleans, LA 70118.
Developmental and genetic differences of susceptibility to noise trauma
Authors: Henry Kenneth R.
Published: October 2005

Mice of two genotypes were exposed, at one of eight ages, to 2 min of a 124-dB SPL, 8–16 kHz octave band noise. In both genotypes threshold shifts (TS) of evoked cochlear microphonics (CM) and action potentials (AP) were not observed when exposure occurred at 12 days of age, were maximal in 30–36 day exposed mice, and declined with increasing age. TS was greater for AP than for CM, with higher frequencies most severely affected. CBA mice were more severely affected than C57BL/6 mice. In CBA mice, susceptibility to TS paralleled susceptibility to acoustic priming for audiogenic seizures. Exposure at 30–36 days had no immediate observable behavioral effect. But re-exposing these mice 5 days later caused them all to convulse, with 87% of them dying. In contrast, susceptibility to acoustic priming for the C57BL/6 peaked sharply at 18 days of age, not corresponding to its age of peak cochlear susceptibility. Genetically determined differences of auditory brainstem function were hypothesized to account for these strain differences.
Advances in nearfield acoustical holography (NAH) algorithms II: Zoom imaging
Authors: Huang Yanmin , Veronesi William A. , Maynard J. D.
Published: October 2005

In NAH, it is often desirable to increase the density of points in the transform space beyond the density produced by a simple 2-D discrete Fourier transform of the input data array. Two equivalent methods of increasing the density of points are presented. The two methods are: augmenting the original data with zeros before transforming, or convolving the transform of the unaugmented data array with the transform of a two-dimensional square unit step function. Augmenting with zeros and the equivalent convolution approach are based on the assumption that the field is negligible beyond the measured region of the hologram surface. Although the hologram and its transform are two dimensional, the density increasing schemes can be cast in a one dimension at a time form resulting in a great reduction in computation time. This technique has great utility when restricted to increasing the density of points inside the radition circle. When the radiation circle originally contains relatively few points, the direct convolution is faster, also this method is not limited to power of two increases indensity. Results for propagating the pressure field from a baffled piston source are given. [Work supported by ONR and NASA.]
The implementation of nearfield acoustic holography with an array processor
Authors: Lee Yongchun , Maynard J. D.
Published: October 2005

The data reduction capabilities of our nearfield acoustic holography (NAH) system have been greatly enhanced through the development of efficient computer algorithms utilizing an array processor with a minicomputer. The array processor accelerates not only the FFT computation, but also the Green's function calculation, data windowing, graphics display generation, and zoom imaging. In this paper, the various techniques, which have reduced the NAH processing time by a factor of ∼ 20, will be discussed. This new processing system speeds data collection and processing and will permit measurement of radiation from wideband noise sources with a large number of frequency components. [Work supported by ONR and NASA.]
Lecture demonstrations in acoustics
Authors: Carpenter D. Rae , Minnix R. B.
Published: October 2005

Over the last several years we have been involved in training high school teachers to use a variety of physics lecture demonstrations. A selection of those dealing with acoustics will be presented. Although intended primarily for high school and college teachers of physics, they should be of general interest to acousticians. [Work supported in part by NSF.]
Rough surface boundary wave attenuation due to incoherent scatter
Authors: Tolstoy Ivan
Published: October 2005

The incremental energy loss ΔE/E per unit path length for a boundary mode traveling along a rough surface may be calculated from elementary low-frequency scattering approximations, using previously published results [I. Tolstoy, J. Acoust. Soc. Am. 74, 1068–1070 (1983) and 72, 960–972 (1982)]. This allows one to calculate explicitly the attenuation factor exp( − δr), where r is the range, with δ = 12ΔE/E for rough two-fluid interfaces with arbitrary impedances, constraints, and roughness shapes. It is shown that δ = Af6, where f is the frequency and A a parameter which depends upon the size, spacing, and form of the roughness (for close-packed roughness elements A is proportional to the fifth power of the mean roughness height). Given a point source of sound and a receiver on the rough interface the boundary wave amplitude pB ∝ r−1/2 f3/2 exp( − δr) and exhibits, for fixed r, a well-defined maximum in the frequency domain at fM = (4Ar) −1/6 and falls off rapidly for higher frequencies, i.e., it displays a bandpass behavior with slow roll-off at low frequencies. The predictions of this theory agree with recently reported model work [G.L.D'Spain et al., J. Acoust. Soc. Am., in press]. [Work supported by ONR.]
Perturbation theory for scattering from random rough surfaces using the extended boundary condition
Authors: Winebrenner Dale , Ishimaru Akira
Published: October 2005

Scattering from surfaces with roughness small relative to the wavelength of the incident radiation has most often been calculated using the perturbation method developed by Rice. This method uses the Rayleigh hypothesis, i.e., the assumption that the scattered field on the surface can be represented as a sum of up-going plane waves. This assumption is known to be invalid when slopes of the rough surface are sufficiently large. A way of treating scattering using a perturbation theory based on the extended boundary condition has been given by several authors. This method appears to avoid the Rayleigh hypothesis. We will compare the results of the two methods and discuss the connection between them. [Work supported by ONR.]
Some interesting modes of propagation in a large elastic sample
Authors: Hagelberg M. Paul
Published: October 2005

The availability of a large sample of high-quality steel with carefully finished surfaces has made possible time resolution of propagation modes that ordinarily overlap. The resolved echo trains clearly demonstrate several interesting modes of propagation. These observations serve not only to illustrate important features of wave propagation in an elastic medium but also to show the importance of recognizing these features when interpreting results from experiments performed in such media.
Impedance formulation and clipping technique in the fast field program
Authors: Richards R. F. , Lee S. W. , Bong N. , Raspet Richard
Published: October 2005

The propagation of a sound wave in a layered media excited by a point pressure source can be formulated into a Fourier integral. A powerful method for evaluating this integral is to use the Fast Fourier Transform, resulting in the so-called “Fast Field Program (FFP)” [F. R. DiNapoli and R. L. Deavenport, J. Acoust. Soc. Am. 67, 92–105 (1980)]. In the existing scattering matrix formulation, the FFP requires the multiplication of matrices containing exponential factors exp (+γh) and exp (−γh), where γ is the attenuation constant along the vertical direction of a layer, and h is the layer's thickness. These factors often exceed the computer's capability in handling large/small numbers, thus resulting in erroneous FFP solutions. In the present paper, we describe a new formulation of the FFP that is inherently numerically stable and is completely free from the difficulty mentioned above. The central step in our formulation is to calculate the equivalent impedance for each layer in succession starting from the top/bottom layers toward the source. This technique results in terms containing (γh) rather than (−γh), which goes to unity smoothly as γh → ∞. In addition, we introduce a “clipping technique.” For a given horizontal wavenumber, it removes layers that are not physically significant by terminating the preceding layer at its characteristic impedance.