bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating the form of the peripheral nonlinearity from slopes of psychometric functions in forward masking
Authors: Jesteadt Walt , Neely Stephen T. , Schairer Kim S.
Published: October 2013

In previous work, we have shown that slopes of psychometric functions (PF) obtained for the detection of a signal in the presence of a forward masker are in general agreement with standard assumptions concerning the form of the peripheral nonlinearity. PFs are steep for conditions where signal levels are low and grow progressively shallower as the signal threshold increases in level. PFs become more parallel if signal levels are adjusted to reflect the effect of a nonlinearity of the form proposed by Yates et al. [G. K. Yates, I. M. Winter, and D. Robertson, Hear. Res. 45, 203–220 (1990)]. An alternative approach is to use PF data to estimate the form of the nonlinearity. The data suggest that the reciprocal of the slope of the PF is linearly related to the signal level. This would indicate that the nonlinearity is logarithmic. Use of a logarithmic nonlinearity as the first stage in a model of forward masking predicts thresholds as a function of the masker level and signal delay that are consistent with a formula proposed by Jesteadt et al. [W. Jesteadt, S. P. Bacon, and J. R. Lehman, J. Acoust. Soc. Am. 71, 950–962 (1982)] and predicts loudness growth rates consistent with the literature. [Work supported by NIDCD.]
Pyroshock prediction procedures
Authors: Piersol Allan G.
Published: October 2013

Given sufficient effort, pyroshock loads can be predicted by direct analytical procedures using Hydrocodes that analytically model the details of the pyrotechnic explosion and its interaction with adjacent structures, including nonlinear effects. However, it is more common to predict pyroshock environments using empirical procedures based upon extensive studies of past pyroshock data. Various empirical pyroshock prediction procedures are discussed, including those developed by the Jet Propulsion Laboratory, Lockheed-Martin, and Boeing.
Pyroshock data acquisition—historical developments using piezoelectric accelerometers and other transducers
Authors: Himelblau Harry
Published: October 2013

For nearly 50 years, P/E accelerometers have been used for acquiring pyroshock data with mixed results. For longer distances between the explosive source and the transducer location (e.g., two feet or more), valid data of lesser shock magnitude were usually obtained. However, for shorter distances, a variety of problems were often encountered, causing erroneous results. It was subsequentially determined that most problems were caused by measurement system nonlinearities, i.e., the nonlinear resonant response of the accelerometer, or exceeding the linear amplitude range of the signal conditioner and recorder. In the earlier years, it was erroneously assumed that subsequent low pass filtering of the signal would remove the nonlinearities, hopefully leading to valid data. This only masked the invalid results. Eventually, improved P/E accelerometers were developed with higher natural frequencies and larger amplitude limits that caused substantially fewer problems and allowed measurements closer to the explosive sources. Shortly thereafter, the high frequency noncontact laser doppler vibrometer became available which circumvented the accelerometer resonance problem. However, this velocity transducer is almost always limited to laboratory tests in order to constrain the motion of the laser head by a very rigid and massive support foundation compared to the flexible structure which is attached to the laser target. Other LDV measurement problems have been encountered that must be avoided to achieve valid data. Conventional strain gages have been successfully used to measure pyroshock strain. However, due to the short wavelength of direct and bending pyroshock waves at high frequencies, small strain gages are usually required to avoid spatial averaging over the length of the gage.
Pyroshock data analysis—Analysis, editing, and validation
Authors: Smallwood David O.
Published: October 2013

The most common form of pyroshock data analysis is the shock response spectrum (SRS), which is defined and briefly discussed. The most common way to compute the SRS of a time history is with a digital recursive filter that simulates the response of a single-degree-of-freedom (SDOF) system to the pyroshock excitation. This filter is described together with its strengths and limitations. Sometimes additional characteristics of the time history are used to supplement the SRS. The most common is a definition of duration. If the time history is assumed to be a sum of exponentially decaying sinusoids, a decay rate can be used. Often, the time duration is defined as the duration until the waveform decays to 10% of its peak value. More recently temporal moments have been used to define the temporal characteristics of the waveforms. Flaws in pyroshock data are common, including accelerometer zero shifts, clipped data, dropouts, and instrumentation overloads. Data validation procedures that expose many of these flaws are outlined. Good pyroshock data are difficult to acquire. As a general rule, flawed data should not be used, but sometimes we are forced to use flawed data. Procedures are briefly described for editing flawed data that will result in credible, although not necessarily correct, results.
Perception of the English intrusive stops by Korean listeners
Authors: Han Jeong-Im
Published: October 2013

This paper reports results of an experiment examining Korean listeners’ perception of English intrusive stops in nasal-obstruent clusters. The experiment tests (1) how often intrusive stops are perceived; (2) how language-specific syllable structure constraints influence the perception, given the fact that Korean does not allow consonant clusters in syllable onsets and codas; (3) whether even the perception of phonetic variables like intrusive stops, not phonemes, could be improved by learning. Ninety English non-words with a monosyllable structure of CVC1C2 were created, where C1=/m,n,N/, and C2=/p,k,s/. The stimuli including additional 90 filler items were recorded by three native English speakers and one representative data among them was given to three groups of native Korean listeners in terms of their English proficiency. Each was asked to monitor the target sounds [Warner and Weber, J. Phonetics 29, 23–52 (2001)]. The preliminary results show that identification of intrusive stops in English is totally dependent on Korean syllable structure, so even stimuli with strong acoustic cues were misparsed. Nonetheless, there’s a high correlation between perception of intrusive stops and listeners’ English proficiency, showing the possibility of the improvement of perception by learning.
Effects of consonantal context on perception of French rounded vowels by American English adults with and without French language experience
Authors: Levy Erika S. , Strange Winifred
Published: October 2013

This study extended Gottfried’s [J. Phonetics 12, 91–114 (1984)] investigation of the effects of learning French on AE listeners categorial discrimination of the contrasts involving Parisian French vowels /y/, /o//, /u/, and /i/. Vowels were presented in /rabVp/ and /radVt/ bisyllables embedded in carrier phrases by three different speakers in an AXB discrimination task. Two groups were tested: proficient L2-French-speaking AE listeners (Exp) and non-French-speaking AE listeners (Inexp). Overall, the Exp group performed better than the Inexp group on /u-o//, /y-i/, and /y-o// distinctions (mean errors: Exp=5%, Inexp=24%). However, for /u-y/, the groups did not differ (Exp=30% vs Inexp=24% errors). The findings may be explained by perceptual assimilation patterns, which are determined, in part, by consonantal context. The Inexp group confused /y/ with /i/ in bilabial context, but /y/ with /u/ in alveolar context, whereas the Exp group confused /y/ with /u/, in both contexts. For all contrasts, the Inexp group performed better in bilabial than in alveolar context (16% vs 32% errors), whereas no context effect was revealed for the Exp group. The results suggest that learning a foreign language includes learning its coarticulatory rules.
Cross-language perception of fricative/vowel syllables by speakers of English and Mandarin
Authors: Radhakrishnan Sreedivya , Schmidt Anna
Published: October 2013

A recent study [Radhakrishnan and Schmidt (2001)] on the perception of fricative/vowel syllables by English and Mandarin speakers demonstrated that English speakers use the fricative noise while Mandarin speakers use both the fricative noise and vowel transitions in categorizing syllable initial fricatives in their native languages. In this study, cross-language mappings for fricative/vowel syllables were obtained from native English and Mandarin speakers. Native English and Mandarin speakers labeled and rated three sets of tokens from L2. These tokens were (1) fricative noises from four different vowel environments, (2) natural fricative vowel syllables, and (3) F+V combinations in which the fricative noise from one language was combined with vowel transition from the other language. Vowel length was manipulated in the third set of stimuli. Results indicate differences in the cross-language mappings by the two language groups.
Spectral resolution and English experience: effects on English phoneme and word recognition by non-native English speakers
Authors: Padilla Monica , Shannon Robert V.
Published: October 2013

Normal hearing listeners whose first language was Spanish were tested with English phonemes, words and sentences. Listeners were divided into four categories according to experience with the second language. Speech was presented in a sound treated booth at a level of 70 dBA. Listening conditions included noise (SNR of 15 dB, 10 dB, 5 dB, 0 dB, and 5 dB) and reduced spectral information (2, 4, 6, 8 and 16 frequency bands). Plomp’s Model [J. Speech Hear. Res. 29, 146–154 (1986)] was applied to the data. The distortion factor ‘‘D’’ defined by Plomp was found to increase with an increased loss of spectral resolution. It was also found to increase with age of learning of the second language. An additional ‘‘distortion’’ seems to be introduced when a second language is learned at a later age. Non-native listeners had more difficulty understanding vowels, words and sentences. Surprisingly, English experience had less effect on word and sentence recognition than on vowel recognition. Significantly lower performance on vowel recognition was seen even for fully bilingual listeners with reduced spectral resolution which could probably be related to the conflicting vowel spaces of the two languages. [Work funded by NIDCD.]
Effects of training on learning non-native speech contrasts
Authors: Sinnott Joan M.
Published: October 2013

An animal psychoacoustic procedure was used to train human listeners to categorize two non-native phonemic distinctions. In Exp 1, Japanese perception of the English liquid contrast /r-l/ was examined. In Exp 2, American-English perception of the Hindi dental-retroflex contrast /d-D/was examined. The training methods were identical in the two studies. The stimuli consisted of 64 CVs produced by four different native talkers (two male, two female) using four different vowels. The procedure involved manually moving a lever to make either a ‘‘go-left’’ or ‘‘go-right’’ response to categorize the stimuli. Feedback was given for correct and incorrect responses after each trial. After 32 training sessions, lasting about 8 weeks, performance was analyzed using both percent correct and response time as measures. Results showed that the Japanese listeners, as a group, were statistically similar to a group of native listeners in categorizing the liquid contrast. In contrast, the Amercan-English listeners were not nativelike in categorizing the dental-retroflex contrast. Hypotheses for the different results in the two experiments are discussed, including possible subject-related variables. In addition, the use of an animal model is proposed to objectively ‘‘calibrate’’ the psychoacoustic salience of various phoneme contrasts used in human speech.
Release bursts in English word-final stops: A longitudinal study of Korean adults’ and children’s production
Authors: Tsukada Kimiko , Mack Molly , Sung Hyekyung , Birdsong David , Bialystok Ellen
Published: October 2013

Stops at the end of Korean words are always unreleased. The question addressed here was whether Korean adults and children living in the U.S. can learn to release stops at the end of English words. Four groups of 18 native Koreans (NK) who differed according to age (adult versus child) and length of residence in the U.S. (3 vs 5 years at T1) participated. Two native English (NE) groups served as age-matched controls. Production data were collected at two times (T1, T2) separated by one year. English words ending in /t/ and /k/ were then examined in perception experiments (Exp. 1, Exp. 2). NE-speaking judges decided whether the final stop has a release burst or not. Exp. 1 showed that NE talkers released /t/ more often than NK talkers did. The effect of time was also significant. Talkers produced release bursts more often at T2 than at T1. Exp. 2 showed that, unlike Exp. 1, there were significant differences between NK adults and children. While NK children did not differ from NE children, NK adults released the final /k/ much less often than NE adults did. Possible reasons for why the expected children’s advantage was seen for /k/, but not for /t/, will be discussed. [Work supported by NIH.]
Acquisition of Japanese contracted sounds in L1 phonology
Authors: Tsurutani Chiharu
Published: October 2013

Japanese possesses a group of palatalized consonants, known to Japanese scholars as the contracted sounds, [CjV]. English learners of Japanese appear to treat them initially as consonant + glide clusters, where there is an equivalent [Cj] cluster in English, or otherwise tend to insert an epenthetic vowel [CVjV]. The acquisition of the Japanese contracted sounds by first language (L1) learners has not been widely studied compared with the consonant clusters in English with which they bear a close phonetic resemblance but have quite a different phonological status. This is a study to investigate the L1 acquisition process of the Japanese contracted sounds (a) in order to observe how the palatalization gesture is acquired in Japanese and (b) to investigate differences in the sound acquisition processes of first and second language (L2) learners: Japanese children compared with English learners. To do this, the productions of Japanese children ranging in age from 2.5 to 3.5 years were transcribed and the pattern of misproduction was observed.
Acoustic correlates of Georgian ejectives
Authors: Wysocki Tamra M.
Published: October 2013

In this paper we present results from acoustic analysis of Georgian ejectives. Georgian, a language of the Kartvelian (South Caucasian) family, has a three-way opposition for voiced, voiceless aspirated and ejective stops. There have not been many acoustic studies of ejectives; those studies that discuss ejectives, such as by Lindau [J. Phonetics 12, 147–155 (1984)], report cross-linguistic variation in timing between oral and glottal releases and the onset of a following vowel. In this paper we investigate acoustic correlates of Georgian ejectives and examine how these correlates are realized in two-member ejective clusters. Additionally, correlates of Georgian ejectives are compared to findings from previous studies and discussed in relation to cross-linguistic tendencies and variation. Data consist of field recordings of three native Georgian speakers producing single ejectives and ejective clusters in word-initial and word-medial (intervocalic) positions at a normal rate of speech. Acoustic analysis was completed using spectrograms and waveforms. Results indicate that, while there is variation within and among speakers, characteristics correlated with singleton Georgian ejectives include relative burst amplitude, noise quality following oral release, long, positive voice onset time, and a short period of creaky voice at the onset of a following vowel. Some of these characteristics differ from those of ejective clusters.
Perception and analysis of Spanish accents in English speech
Authors: Chism Cori , Lass Norman
Published: October 2013

The purpose of the present study was to determine what relates most closely to the degree of perceived foreign accent in the English speech of native Spanish speakers: intonation, vowel length, stress, voice onset time (VOT), or segmental accuracy. Nineteen native English speaking listeners rated speech samples from 7 native English speakers and 15 native Spanish speakers for comprehensibility and degree of foreign accent. The speech samples were analyzed spectrographically and perceptually to obtain numerical values for each variable. Correlation coefficients were computed to determine the relationship beween these values and the average foreign accent scores. Results showed that the average foreign accent scores were statistically significantly correlated with three variables: the length of stressed vowels (r=−0.48, p=0.05), voice onset time (r =−0.62, p=0.01), and segmental accuracy (r=0.92, p=0.001). Implications of these findings and suggestions for future research are discussed.
History of signal processing in acoustics
Authors: Havelock David I.
Published: October 2013

The Technical Committee on Signal Processing in Acoustics is the youngest of the ASA’s 13 Technical Committees. It was formed as an Interdisciplinary Technical Group in Fall 1994 and was converted to a Technical Committee in Fall 2000. It has had over 120 technical sessions, cosponsoring sessions with all of the other Technical Committees. Signal processing first appeared as a distinct
Computer modeling in the practice of acoustical consulting: An evolving variety of uses from marketing and diagnosis through design to eventually research
Authors: Madaras Gary S.
Published: October 2013

The use of computer modeling as a marketing, diagnosis, design, and research tool in the practice of acoustical consulting is discussed. From the time it is obtained, the software can be used as an effective marketing tool. It is not until the software basics are learned and some amount of testing and verification occurs that the software can be used as a tool for diagnosing the acoustics of existing rooms. A greater understanding of the output types and formats as well as experience in interpreting the results is required before the software can be used as an efficient design tool. Lastly, it is only after repetitive use as a design tool that the software can be used as a cost-effective means of conducting research in practice. The discussion is supplemented with specific examples of actual projects provided by various consultants within multiple firms. Focus is placed on the use of CATT-Acoustic software and predicting the room acoustics of large performing arts halls as well as other public assembly spaces.
Applications of computer modeling at Wrightson, Johnson, Haddon & Williams, Inc
Authors: Johnson James A. , Seep Benjamin C.
Published: October 2013

Computer modeling has become useful as an investigative tool and as a client communication and explanation tool in the field of acoustical consulting. A variety of in-house developed and commercially available applications is in constant use at the firm of Wrightson, Johnson, Haddon & Williams. Examples likely to be demonstrated (depending on time) include use of digital filtering for building exterior noise reduction comparisons, a shell isolation rating (SIR) model, simple sound barrier programs, an HVAC spreadsheet, a visual sightline modeling tool, specular sound reflections in a semicircular arc, and some uses of CATT-acoustic auralizations.
Practical considerations in using audible simulation technology
Authors: Tyson Thomas , Jacob Kenneth
Published: October 2013

Ideally, consultants and clients alike would like to hear sound from computer models that is indistinguishable from the sound of the finished project. No one, however, would claim perfection in computer modeling, and differences between the model and the finished project certainly remain. How can practitioners in the field know exactly what these differences are, and more importantly, how they may affect the outcome of their work? Said a different way, how much can they and their clients trust what they hear from their computer models? In the work presented here, an approach used to answer these questions in the case of Boses Modeler and Auditioner programs is given. The approach is explained using: (1) laboratory results that focus on the critical dimension of speech intelligibility and (2) comparisons of actual system installations from the past seven years that were modeled and presented to end users using the Auditioner system.
What can be learned from one of nature’s most advanced biosonars: Discussion on Bottlenose dolphins echolocation waveforms with respect to echolocation tasks in shallow water
Authors: Olivieri Marc P.
Published: October 2013

This paper presents recent findings on the biosonar echolocation waveforms of Bottlenose dolphins (Tursiops truncatus). The complex spectral shape of the waveforms (bimodal spectrum) and the dynamics of the click trains are discussed. It is shown that these waveforms have not only the smallest possible time-bandwidth product, but that they are in fact minimum phase waveforms (i.e., the phase is a function of the autospectrum). The characteristics of the waveforms including time/frequency distribution, autocorrelation, and the bimodal spectral structure of these waveforms are discussed. An interpretation of these features is proposed with respect to echolocation tasks in shallow water. It is shown how these waveforms may be used for optimizing both near range resolution and sidelobe levels in the processed echo waveforms. Examples are shown on how GORCA Technologies, Inc. (GTI) exploits such features in the development of a biomimetic SONAR. Finally, this paper presents examples of GTIs proprietary broadband adaptive algorithm performance, using animal echolocation data. In the data used for this study, the animal performed a three-alternative match-to-sample task (data courtesy of the biosonar program at SPAWAR San Diego). [Work sponsored by ONR.]
Nocturnal location and activity of Pacific coast bottlenose dolphins determined by a sonobuoy array
Authors: Howarth Eric S. , Defran R. H.
Published: October 2013

Pacific coast bottlenose dolphins (Tursiops truncatus) move offshore, presumably to feed as the sun sets [Hanson and Defran (1993), Ward (1998), Day (1998)] and are most often found inshore on the surfline at sunrise. The purpose of this research was to document their activity and location during nocturnal hours. A sonobuoy array was deployed in a triangle configuration centered approximately 500 m from the mean low low water line at Torrey Pines State Beach, CA. Surveys were conducted for 11 nights between October 1999 and November 1999 and for 21 nights between August 2000 and December 2000. Dolphin vocalizations were detected on 26 of 33 nights.
Specialization of the auditory processing in harbor porpoise, characterized by brain-stem potentials
Authors: Bibikov Nikolay G.
Published: October 2013

Brain-stem auditory evoked potentials (BAEPs) were recorded from the head surface of the three awaked harbor porpoises (Phocoena phocoena). Silver disk placed on the skin surface above the vertex bone was used as an active electrode. The experiments were performed at the Karadag biological station (the Crimea peninsula). Clicks and tone bursts were used as stimuli. The temporal and frequency selectivity of the auditory system was estimated using the methods of simultaneous and forward masking. An evident minimum of the BAEPs thresholds was observed in the range of 125–135 kHz, where the main spectral component of species-specific echolocation signal is located. In this frequency range the tonal forward masking demonstrated a strong frequency selectivity. Off-response to such tone bursts was a typical observation. An evident BAEP could be recorded up to the frequencies 190–200 kHz, however, outside the acoustical fovea the frequency selectivity was rather poor. Temporal resolution was estimated by measuring BAER recovery functions for double clicks, double tone bursts, and double noise bursts. The half-time of BAERs recovery was in the range of 0.1–0.2 ms. The data indicate that the porpoise auditory system is strongly adapted to detect ultrasonic closely spaced sounds like species-specific locating signals and echoes.
An experimental/numerical study of nonlinear standing waves in resonantors
Authors: Finkbeiner Joshua R. , Li Xiaofan , Raman Ganesh , Daniels Christopher , Steinetz Bruce
Published: October 2013

The generation of shock-free high-amplitude pressure waves in resonators promises to become a powerful and useful technology. Lawrenson et al. [J. Acoust. Soc. Am. Aug. (1998)] described the generation of shock-free high-amplitude pressure using large equipment and resonators to produce the reported effects. An attempt is made to generate shock-free high-amplitude pressure waves using relatively small resonators excited by a small linear motor. Ambient air is used as the working fluid. A small cylindrical resonator is tested resulting in the lack of the expected shocked waveform while a larger model of the same shape exhibits shocking behavior. A small conical resonator produces shock-free pressure waves at resonance, but the amplitude of these waves is small. A larger cone resonator model produces shock-free pressure waves of higher amplitude. A large horn-cone resonator also produces shock-free high-amplitude pressure waves. A numerical model solves the governing equations using a shooting method. The numerical results are compared to the experimental results. The difficulties caused by structural resonances, which are separate from the desired fluid resonances and caused by approaching the natural frequency of the linear motor/resonator structure, are shown and discussed.
Does the European free reed really originate from Asia?
Authors: Braasch Jonas , Ahrens Christian
Published: October 2013

Free reeds can be found in European instruments like the accordion and reed organ. Christian Gottlob [Theophil] Kratzenstein was the first scientist in Europe to use a free reed when he built his speech-imitating machine, and it is believed throughout literature that he copied the mechanism of a free reed from the Asian mouth organ. However, after analyzing Kratzenstein’s original work (Tentamen Resolvendi Problema ab Akademia Scientiarum Imperiali Petropolitana ad Annum 1780 Publicae Propositum) it was rather concluded that his free-reed design was modified from a striking reed pipe of an organ because he recorded that he wanted to reduce the rattle of his speech-imitating machine by modifying the reed. Furthermore, he did not mention the mouth organ at all in his work. An additional evidence for this hypothesis is his detailed figures of his speech imitating machine. They show clearly that the only difference between his free reed and the striking reed pipe of an organ is the smaller size of the reed in order to fit through the shallot. In contrast, Asian free reeds are flat, have no tuning wire, and the reed and reed opening are made from the same piece of metal.
The acoustics of plasma-sprayed, thick-thermal-barrier coatings
Authors: Harris John
Published: October 2013

Plasma-sprayed, thick-thermal-barrier coatings are very porous, approximately 2 mm thick, coatings used to insulate metal engine parts from high-temperature combustion processes. They are grown such that their elastic constants and density increase with depth; at the surface the elastic constants take small values, especially the shear modulus which is very small, but rapidly increase to those typical of the metal substrate. A Thomson–Haskell matrix technique is used to find numerically the eigenmode(s) along each vertical line through the coating and substrate, at each station along the direction of propagation. Using the lowest eigenmode, calculated at each station, a JWKB approximation to propagation in a coating with variable thickness is calculated, and from this the changes in travel time caused by varying degress of spalling at the surface are worked out. Using the two or three lowest eigenmodes for a coating of uniform thickness, a coupled-mode calculation is used to determine to what degree an interfacial inclusion couples the lowest eigenmode into the next higher one. In both cases the goal is to calculate the changes caused by the defects so that their presence may be detected. [Work supported by NSF.]
Pyroshock design
Authors: Piersol Allan G.
Published: October 2013

The structural response velocities produced by pyroshocks are usually too low to cause structural damage beyond the immediate region of the pyrotechnic device where damage is intended. On the other hand, pyroshocks can cause malfunctions of equipment mounted near the pyrotechnic device, particularly equipment containing microelectronic or ceramic elements. These malfunctions are usually the result of the high frequency content (above 2 kHz) of pyroshocks, and are difficult to design against using conventional analysis procedures. On the other hand, adherence to simple design guidelines, which are summarized, can substantially suppress pyroshock-induced failures of equipment.
Effects of category learning on auditory perception and cortical maps
Authors: Guenther Frank H.
Published: October 2013

Our ability to discriminate sounds is not uniform throughout acoustic space. One example of auditory space warping, termed the perceptual magnet effect by Kuhl and colleagues, appears to arise from exposure to the phonemes of an infant’s native language. We have developed a neural model that accounts for the magnet effect in terms of neural map dynamics in auditory cortex. This model predicts that it should be possible to induce a magnet effect for non-speech stimuli. This prediction was verified by a psychophysical experiment in which subjects underwent categorization training involving non-speech auditory stimuli that were not categorical prior to training. The model further predicts that the magnet effect arises because prototypical vowels have a smaller cortical representation than non-prototypical vowels. This prediction was supported by an fMRI experiment involving prototypical and non-prototypical examples of the vowel /i/. Finally, the model predicts that categorization training with non-speech stimuli should lead to a decreased cortical representation for stimuli near the center of the category. This prediction was supported by an fMRI experiment involving categorization training with non-speech auditory stimuli. These results provide strong support for the model’s account of the effects of category learning on auditory perception and auditory cortical maps.
Internal structure of phonetic categories: Some characteristics and constraints
Authors: Miller Joanne L.
Published: October 2013

A widely held assumption in the speech perception literature for many years was that during the course of processing listeners derive an abstract phonetic representation and, in doing so, discard information about the fine-grained detail of the speech signal. However, more recent research has shown that the representations of speech are much richer than this emphasis on abstract categories would suggest, and that listeners retain in memory a substantial amount of fine-grained acoustic-phonetic information. One line of evidence for the richness of phonetic representations comes from research showing that phonetic categories are internally structured in a graded fashion, with some members of the category perceived as better exemplars (as more ‘‘prototypical’’) than others. In this talk I will describe findings from our research program that highlight some of the characteristics of these internally structured categories, and discuss how these characteristics place constraints on models of phonetic perception. [Work supported by NIDCD.]
Construction of high frame rate images with Fourier transform
Authors: Peng Hu , Lu Jian-yu
Published: October 2013

Traditionally, images are constructed with a delay-and-sum method that adjusts the phases of received signals (echoes) scattered from the same point in space so that they are summed in phase. Recently, the relationship between the delay-and-sum method and the Fourier transform is investigated [Jian-yu Lu, Anjun Liu, and Hu Peng, ‘‘High frame rate and delay-and-sum imaging methods,’’ IEEE Trans. Ultrason. Ferroelectr. Freq. Control (submitted)]. In this study, a generic Fourier transform method is developed. Two-dimensional (2-D) or three-dimensional (3-D) high frame rate images can be constructed using the Fourier transform with a single transmission of an ultrasound pulse from an array as long as the transmission field of the array is known. To verify our theory, computer simulations have been performed with a linear array, a 2-D array, a convex curved array, and a spherical 2-D array. The simulation results are consistent with our theory. [Work supported in part by Grant 5RO1 HL60301 from NIH.]
Inverse source problem by convex optimization with constraints over the object space and signal field
Authors: Teramoto Kenbu
Published: October 2013

In the acoustical endscopy, due to the physical limitations, the transducer array is composed of a small number of elements and each interspacing is larger than the acoustical wavelength that is called a sparse array system. In such cases, avoiding the ill-posed problems, projection onto convex sets (POCS) methods are used with incorporating constraints about both the signal field and the object space. POCS, however, is based on the alternating projections paradigm, which has a slow-convergence property in general. Furthermore if inconsistency exists in the set of constraints, this POCS algorithm cannot guarantee the convergence to the optimal estimate. The proposed algorithm is based on convex optimization over the direct product of the object space and the observed signal field. By acoustical experiments, it is proved that the proposed algorithm has the following improvements: (1) Targets can be identified when unknown components exist in the transfer function. (2) Transient behavior of the convergence becomes more stable than that of POCS algorithm. (3) Instability caused by the inconsistency in the constraints can be reduced. (4) Artifacts caused by the spurious lobes can be reduced under the condition that the interspacing of transducer elements is larger than the wavelength.
Extensions to the method of complex images
Authors: Fawcett John A.
Published: October 2013

In an earlier paper [J. A. Fawcett, J. Acoust. Soc. Am. 108, 2791–2795 (2000)] the application of the method of complex images to approximating the half-space acousto-elastic Green’s function was described. In this paper, extensions to this theory are presented. It is shown that the method can be used for layered half-spaces. For a uniform half-space, analytic time domain expressions are derived for a propagating pulse. By using the complex images in a manner analogous to image theory for a perfect waveguide, the method can be used to approximate a waveguide’s Green’s function. The Green’s function described by the complex image method is accurate for near-field to far-field ranges and is ideal for many propagation and scattering modeling applications.
Seismo-acoustic inversion of shallow water data using genetic algorithms
Authors: Ruppel Timothy H.
Published: October 2013

Peter Gerstoft’s seismo-acoustic inversion system uses a Genetic Algorithm to search the parameter space and to estimate the errors in the inversion results, and allows the selection of one of several forward models in the inversion process. The current paper tests this system using data from an experiment conducted off the coast of Panama City by Steve Stanic in the summer of 2001. In the experiment, a vertical array was placed in shallow (6.62 m depth) water and ensonified by a submerged source at distances ranging from 20 m to 90 m. In addition, a number of environmental measurements were taken, making this a suitable data set for acoustic inversion. The SAGA system will be used with several forward models for a comparison. [Work supported by the ONR Program Element No. 62435N.]
Case studies of computer model applications in consulting practice
Authors: Siebein Gary , Paek Hyun , LoRang Mark , McGuinnes Courtney
Published: October 2013

Six case studies of computer model applications in a consulting practice will be presented to present the range of issues that can be studied with computer models as well as to understand the limitations of the technique at the present time. Case studies of elliptical conference rooms demonstrate basic acoustic ray principles and suggest remediation strategies. Models of a large themed entertainment venue with multiple amplified sound sources show how visualization of the acoustic ray paths can assist a consultant and client in value engineering locations and amounts of acoustic materials. The acoustic problems with an angled ceiling and large rear wall were studied when an historic church was converted to a music performance hall. The computer model of an historic hall did not present enough detailed information and was supplemented with physical model studies and full size mock-up tests of the insertion of an elevator door that would open directly into the concert room. Studies to demonstrate the amount of room model detail to obtain realistic auralizations were also conducted. The integration of architectural acoustic design and audio system design were studied in computer models of a large church sanctuary.
Acoustic surveys for Mexican spotted owls (Strix occidentalis lucida): An analysis
Authors: Bowles Ann E. , Martindell Chris , Plotkin Kenneth J. , Ikelheimer Bruce , Lavallee Tim
Published: October 2013

During acoustic surveys for Mexican spotted owls, the effective detection range is presumed to be 0.25 mi (433 m). However, variations within and between surveys are observed, leading to a variance in owl density estimates. While owl behavior may explain some variation, topography and ambient noise are also likely to be important. To determine the influence of these factors, data from acoustic surveys for Mexican spotted owls in the Gila National Forest (April–July, 2000–2001) were examined. Measurements of owl and human call levels were made with a Sony TCD-10 Pro II DAT equipped with an ACO 7013 microphone. Ambient noise was collected using 40 Larson-Davis 820 and 824 sound level meters in owl activity centers. Wyle Laboratories NMSIM software was used to model propagation of owl and human calls. Owls produced calls with estimated maximum source levels of 92–98-dB SPL. Human callers produced maximum source levels of 88–95-dB SPL. Detection was possible out to more than 2 km under ideal conditions, but topography and ambient noise had a large effect. Corrections for these factors would greatly improve estimates of area surveyed, and thus owl density estimates. [Work supported by the U.S. Air Force, Air Combat Command.]
Acoustical and functional analysis of Mountain lion (Puma concolor) vocalizations
Authors: Potter Jacquelyn
Published: October 2013

A 2-year study resulted in acoustic analysis of the structure of over 900 mountain lion vocalizations recorded in a seminatural setting at Wildlife Prairie Park near Peoria, Illinois. A vocal repertoire was obtained by describing quantitative variables about the sounds, i.e., frequency of the dominant part of the sound (beginning, ending, maximum, and minimum), duration, and number of components. Other variables described the tonal, harmonic, and wideband qualities of the sounds. Behavioral data were collected during the same period. Further analysis of both acoustic and behavioral data was completed to develop a correlation matrix between vocalizations and behavior. This study also looked at the effects of seasons on vocal behavior. Correlations were found between vocalization types and rates of usage with specific behaviors. Vocalization type and the usage rate also varied by season.
Shape of a clamped stiff harpsichord wire driven at a resonant frequency
Authors: Hanson Roger J. , Macomber Hilliard Kent , Boucher Mathew A.
Published: October 2013

A wire transversely driven by a sinusoidal force at the resonant frequency of a vibrational mode vibrates at the driving frequency and at harmonics generated by nonlinear processes in the wire. If the amplitude of a harmonic is measured as a function of position along the wire, its shape is revealed. It differs significantly from a sinusoid in the vicinity of either end of the wire because the ends are clamped and the wire has significant stiffness. The shapes of various harmonics have been determined for a brass harpsichord wire, 70 cm long, from optical detector measurements made at different distances from a clamped end. Knowledge of shape facilitates the determination of antinode amplitudes of harmonics when the gross motion of the wire is so large that the detectors must be positioned near an end of the wire because of their very limited dynamic range. Some observations of harmonics and related phenomena were reported previously [Hanson et al., J. Acoust Soc. Am. 108, 2592 (2000); 106, 2141 (1999)]. The shape information is also needed to help separate nonlinear effects possibly occurring in the detectors from those of interest, occurring in the wire itself.
National policy on the effects of underwater noise on marine mammals and turtles
Authors: Gentry Roger L.
Published: October 2013

Marine anthropogenic noise is increasing at an unknown rate yet its effects on mammals and turtles are poorly documented. Such information is central to noise standards for marine animals required by two federal laws (MMPA and ESA). Good policy on underwater noise would set standards that are neither too liberal (thereby threatening the well being of marine animals), nor too conservative (thereby unnecessarily impairing essential human activities at sea). This balance must be found using existing data; standards cannot await new research. Policy must also lay out rules governing the introduction of novel underwater sound sources whose effects on animals are unknown. Should policy forbid such introductions until all possible consequences are known, or does a safe, incremental method of introduction exist? Should exceptions be made for novel sources associated with national defense? Policy must cope with sound sources that are outside the reach of U.S. federal regulations, such as international shipping. Finally, policy must frame the questions about underwater noise in a way that research can answer. Specifically, how much noise exists, how fast is it growing, where is it, and what consequences does it have for animals and their ecosystems?
Determination of background sound level for use with Massachusetts community sound level criteria
Authors: Tocci Gregory
Published: October 2013

In the early 1970s, the Commonwealth of Massachusetts began the use of their community sound level criteria. In 1990, these criteria were formalized as Policy 90-001. The policy states that: A source of sound will be considered to be violating the Department’s noise regulation (310 CMR 7.10) if the source increases the broadband sound level by more than 10 dB(A) above the ambient. Ambient is defined as the background A-weighted sound level that is exceeded 90% of the time measured during equipment operating hours. The Policy also address tonal sound, and this will be described, but the primary concern of this presentation is the measurement of background sound. A number of background sound measurement strategies will be discussed and a recommendation made on how background should be measured and analyzed that is easily understood by regulators, developers, and the community.
Revisiting the NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure
Authors: Murphy William J. , Franks John R.
Published: October 2013

In 1998, the National Institute for Occupational Safety and Health (NIOSH) revised the Criteria for a Recommended Standard: Occupational Noise Exposure [DHHS (NIOSH) Publication No. 98-126]. NIOSH reevaluated the recommended exposure limit (REL) for occupational noise exposure and reaffirms support for 85-dBA REL. Based upon scientific evidence, NIOSH recommends a 3-dB exchange rate. NIOSH recommends that significant threshold shift be identified as an increase of 15 dB in the hearing threshold level at 500, 1000, 2000, 3000, 4000, or 6000 Hz in either ear, with two consecutive audiometric tests. The new criterion has the advantages of a high identification rate and a low false-positive rate. In contrast with the former 1972 criterion, NIOSH no longer recommends age correction on individual audiograms. NIOSH has revisited its recommendations on the using of single-number laboratory-derived Noise Reduction Rating (NRR) required by the U.S. Environmental Protection Agency for labeling of hearing protectors sold within the United States. In 1972, NIOSH recommended the use of the full NRR value; however, the new criterion recommends derating the NRR by 25%, 50%, and 70% for earmuffs, formable earplugs, and all other earplugs, respectively. This presentation will compare and contrast current regulations against the NIOSH recommendations.
Public policy issues in animal bioacoustics
Authors: Bowles Ann E. , Hastings Mardi C.
Published: October 2013

Control of anthropogenic noise in many terrestrial and underwater environments is crucial for maintaining communication, health, and normal behavior of animals. Noise can be an issue for any species; usually, however, endangered and threatened species and marine mammals are the ones provided legal protection under the Endangered Species Act and/or the Marine Mammal Protection Act. Recent substantiated noise effects in the ocean have received much publicity and generated a more global approach to noise control. However, there are also cases where publicity was not accompanied by scientific data substantiating effects (e.g., an incident involving a $1 million noise barrier installed to protect passerine birds). The public and environmental managers have had difficulty developing adequate guidelines not only because necessary data are often lacking, but also because the manner in which funding is allocated—noise-producing agencies or private organizations are often pressured to fund studies—gives rise to inevitable conflicts of interest (or the perception thereof). Examples of recent noise-related controversies will be presented to examine the role of scientists, engineers, and professional organizations such as ASA in dealing with conflicts of interest and formulating public policy.
Community-based environmental noise management
Authors: Finegold Lawrence S.
Published: October 2013

After a series of major successes in implementing national environmental noise policies from the 1960s to the 1980s, the U.S. has not kept up with improvements in environmental noise policies seen in other areas of the world, most notably in Europe during the past decade. The cessation of funding for the EPA Office of Noise Abatement and Control (ONAC) in 1981 was a defining point in the history of U.S. environmental noise policy, leading to a virtual stoppage of the development of new noise regulations. The Noise Control Act (NCA) of 1972, which established EPA ONAC, was never rescinded after ONAC funding was abolished, but it is not being implemented either. Thus national noise policies are generally not being enforced, except for aircraft certification regulations, and help for state and local efforts is inadequate. In this paper we describe an evolving concept, community-based environmental noise management, to provide practical guidance to local communities in developing noise management strategies. This concept includes components such as local noise ordinances, coordination with State and Federal agencies, incentive and cost-sharing programs, land use planning, an updated environmental impact analysis process, and a negotiation and dispute resolution process. Each of these will be briefly discussed.