bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of different measurement technologies for the in-flight assessment of radiated acoustic intensity
Authors: Klos Jacob , Palumbo Daniel L. , Buehrle Ralph D. , Williams Earl G. , Valdivia Nicolas , Herdic Peter C. , Sklanka Bernard
Published: October 2013

Near-field acoustical holography (NAH) microphone array measurement technologies are currently being investigated for use in aircraft for determining the sound intensity that is radiated through a trimmed aircraft fuselage. Two types of microphone array geometries are studied in this effort, spherical and conformal to the sidewall. Due to the complexity of the interior sound field and in-flight excitation, questions have arisen concerning the capability of array techniques to measure these desired acoustic quantities. The main questions relate to the agreement between array measurements and traditional two-microphone intensity probe measurements and the sensitivity of array measurements to backside sources present in the aircraft cabin. Thus, an investigation was performed in which the NAH array results were compared to intensity probe results measured in the NASA Langley Structural Acoustic Loads and Transmission facility, the Boeing Interior Noise Test Facility, and in flight on the NASA Aries 757 aircraft. An overview of this test sequence and a comparison of NAH, IBEM, and two-microphone intensity probe measurements are made. These comparisons show the relative behavior of the different measurement techniques in both idealized laboratory and realistic in-flight environments. Conclusions are drawn concerning the use of array measurements to assess the sound intensity transmitted through an aircraft sidewall in-flight.
Acoustical imaging by the use of local basis functions
Authors: He Lei , Bolton J. Stuart
Published: October 2013

Experimental acoustical source imaging has been studied extensively, and many methods have been proposed to address this issue. Generally, the acoustical imaging process is modeled as an estimation problem: i.e., the intention is to estimate the boundary values of a field given measurements of the exterior field value. The imaging methods most commonly used at the moment are the beamforming and nearfield acoustical holography families. In both of these procedures, the basis functions used to represent the boundary value are fixed without regard to the source types to be recovered. It may easily be imagined that some source types can be represented very efficiently by some specific set of basis functions, while for other source types the approximation is poor even when a large number of terms are used. In this paper, the efficient representation of the boundary value is considered to be essential, as is the ability to take advantage of preknowledge: e.g., regions where the source velocity is known to be zero. A general procedure is introduced here which makes use of local basis functions of the type used in image processing applications. The effectiveness of the procedure is illustrated through a planar source imaging example.
A pragmatic re-analysis of sleep disturbance data
Authors: Anderson Grant S. , Miller Nicholas P.
Published: October 2013

The acoustics literature documents several field studies in which aircraft noise was measured in people’s bedrooms while their awakening response was simultaneously monitored. Nearly all the studies produced a dose-response relationship between a single event noise metric and an awakening response. Virtually all of these dose-response relationships pertain to (1) the indoor noise dose produced by a single aircraft flyover and (2) the chances that the noise dose will awaken an average person. These dose-response relationships are too limited for application to a full night of operations and to a realistic population of varying individual sensitivities to awakening. Accounting for multiple aircraft during the night is obviously necessary. Less obvious, but important is the need to account for person-to-person variation in awakening sensitivity to noise. This paper presents a re-analysis of original data from one of the field studies. The re-analysis generalizes the dose-response relationships for behavioral awakening to account for multiple aircraft during the night. Then it further generalizes the results to account for person-to-person variations in awakening. The resulting algorithms are applied to the output of the FAA’s Integrated Noise Model, and contours of percent of the population awakened are computed for a full night of aircraft operations.
Use of the Monte Carlo method for uncertainty analysis of acoustic models and measurements
Authors: Muehleisen Ralph T.
Published: October 2013

The Monte Carlo method is often used to estimate uncertainties in models or measurements when analytic formula are not easily determined and/or when the inputs do not have independent errors. In this work, the use of the Monte Carlo method to estimate uncertainties in several common acoustic measurements is presented. The determination of uncertainty distributions of the input parameters, the generation of correlated input errors, and the use of the Monte Carlo method for determination of output uncertainty is discussed.
The ultimate uncertainty—Subjective assessment?
Authors: Schulte-Fortkamp Brigitte
Published: October 2013

The evaluation of acoustic ambiences is influenced by the context, the point in time, and the place in which sounds appear as well as by people’s minds. It is necessary to take into account the nature of the social world and to realize that values and interests become part of the process of research. With their help people’s behavior, perspectives, and experiences can be explored. Interactions and interrelations between acoustic parameters and phenomena in everyday life can be investigated with regard to people’s expectations. The focus is on people’s everyday life, these data have primacy; the theoretical framework is not predetermined but derives directly from the data and is context-bound. The context of the participants’ lives and work affects their behavior so that it is important to keep in mind that the participants are grounded in their history and temporality. The context of people’s lives, events, and actions is studied in everyday-‘‘real life’’-settings. Their culture does not only consist of the physical environment but also of particular ideologies, values, and ways of thinking. Human response in measurements depends on the way people interpret and make use of their experiences and on the world which they live in.
Technology push, market pull, and the Valley of Death
Authors: Swift Gregory W.
Published: October 2013

The Valley of Death is the gap between fundamental research and product development, where apparently promising technologies can stall or disappear. Fundamental researchers may hope for potential applications of their work, and they try to push technology based on their research. Businesses may hope that new technology might serve their market needs, and they try to find promising new technologies that can be pulled toward practical use. The valley between the researchers and the businesses can be surprisingly twisted and thorny, despite government attempts to build roads across it. The histories of cryogenic engineering in the late 20th century and of thermoacoustics work at Los Alamos offer examples of both useful and misguided strategies in this valley. Although global thermoacoustics R&D has not (yet?) been as successful as cryogenic engineering, thermoacoustics has thus far avoided some of the worst pitfalls in the valley.
The role of thermoacoustics in the world of commercial cooling
Authors: Corey John A.
Published: October 2013

The science of thermoacoustics has been with us for nearly 30 years, but as yet few applications have made their way to the marketplace. Acoustic Stirling cryocoolers (also called pulse-tube Stirling or high-frequency pulse-tube coolers) have been the most successful commercial thermoacoustic devices, because they address a region of the cooling market in terms of temperature and cooling power that is not well served by existing technology. This talk will explore how thermoacoustics might fare in attempting to compete with existing technologies in refrigeration and air conditioning, what niche markets make the most sense as entry points, and how thermoacoustics compares to conventional (kinematic or free-piston) Stirling machines. In particular, why there are relatively few commercial Stirling devices in the marketplace (although Stirling cycle machines have been around for over 150 years) will be discussed, and what lessons learned with Stirlings are applicable to thermoacoustics.
Numerical simulations comparing nonlinear acoustic effects in straight and tapered tubes
Authors: Tuttle Brian C. , Sparrow Victor W.
Published: October 2013

In their efforts to improve the efficiency of an orifice pulse tube refrigerator, Olson and Swift [Cryogenics 37, (769–776 (1997)] reported on the benefit of using an optimal taper angle in the construction of the conical pulse tube. They concluded that this geometry effectively suppressed nonlinear acoustic streaming which was interfering with the desired heat transfer within the device. To investigate further the effects of tube geometry on streaming, a numerical simulation is developed for a tube with varying degrees of taper angle. This 2-D finite-difference model, based on the work of Sparrow and Raspet [J. Acoust. Soc. Am. 90, 2683–2691 (1991)], compares nonlinear acoustic propagation in a straight cylindrical tube with that in a tapered conical tube. Development of the model equations in cylindrical and spherical coordinates as well as refinement of the computational grid near the boundaries are considered. [Work supported in part by ONR.]
Unmasking the harmonics of a complex tone
Authors: Goupell Matthew J. , Hartmann William M.
Published: October 2013

Alternately eliminating and reintroducing a harmonic of a complex tone can cause that harmonic to stand out as a pure tone—separately audible from the rest of the complex-tone background. In the psychoacoustical literature the effect is known as ‘‘enhancement.’’ Further, during those intervals in which a harmonic is eliminated, listeners can hear out a neighboring harmonic—separately audible from the background. The latter effect has been called ‘‘unmasking’’ or ‘‘monaural unmasking.’’ The first quantitative evidence for the monaural unmasking effect has been obtained using a pitch matching experiment. For a 200-Hz complex tone with equal-amplitude (45 dB SPL) harmonics in sine phase, harmonics out to the 16th can be unmasked and matched. Pulsing harmonic n almost always unmasks n+1 but for some listeners and some harmonics, n−1 is systematically unmasked instead. Changing the relative phases among the harmonics greatly changes the probability that n+1 or n−1 will be unmasked. Interpretation of the data is somewhat complicated by pitch shifts, normally repelling the unmasked harmonic away from the pulsed harmonic. Classical place pitch models from the 1970s account for some of the features of unmasking, but not for the phase effects. [Work supported by the NIDCD under grant DC00181.]
Roles of frequency information and spatial information in auditory search
Authors: Suzuki Yôiti , Saze Masato , Sugita Yoichi , Asemi Noriaki , Sakamoto Shuichi
Published: October 2013

Effects of attention on auditory search process were examined with five spatially distributed loudspeakers, each of which radiated a component sound (either a pure tone or a 1/12-octave NBN). The stimulus consisted of five component sounds with different (center) frequencies. The listener’s task was to judge whether or not a target sound was included in the distractors as quickly as possible while minimizing errors [N. Asemi et al., Acta Acustica 89, 346–354 (2003)]. The following three conditions were examined: (1) a control condition with no cue sound; (2) a condition with a preceding cue sound indicating the target sound location; and (3) a probe-signal condition in which 1/8 of the cue sounds provided inconsistent information of frequency and location (probes) while the remainder provided consistent information (primaries). The resultant response times for probes were generally longer than those for primaries. Furthermore, attention windows were observed in both frequency and spatial domains. The effect of the disparities between the cue and target was larger when both the frequency and location differed than when only one of them differed. This result also means that the detection performance becomes better if attention is directed with certain information related to the targets.
The influence of native language phonology on auditory and visual word recognition in Russian–English bilinguals
Authors: Shafiro Valeriy , Kharkhurin Anatoliy
Published: October 2013

Visual and auditory recognition of English monosyllabic words was examined in 21 native Russian bilinguals and 12 monolingual speakers of American English. Stimuli comprised 40 CVC minimal pairs distinguishable by four vowel contrasts. Experiment 1 tested visual word recognition following a semantic categorization task. Sixty of the tested words were previously shown in the categorization task, and 60 were new words, 40 of which represented minimal pair alternatives to previously shown words. In experiment 2 participants listened to all words from each minimal pair spoken by one male and one female speaker, and selected one word from each pair. No significant differences were found in the number of errors made by the bilingual and monolingual participants during visual word recognition. In auditory word recognition, bilingual listeners made significantly more errors on the two vowel contrasts that cannot be differentiated based on their native phonological categories. Auditory errors on these categories strongly and significantly correlated with participant’s age of arrival to the U.S.A. These results demonstrate the influence of native language phonology on auditory, but not visual word recognition by Russian–English bilinguals.
Interaction between speech and numerical processing: A behavioral and fMRI study in bilingual adults
Authors: Lin Jo-Fu Lotus , Raizada Rajeev , Imada Toshiaki , Kuhl Patricia K. , Imada Toshiaki
Published: October 2013

Studies suggest that exact mathematical terms (numbers, multiplication tables) are stored in the language in which they were originally learned. Bilingual adults are less accurate and slower when doing exact mathematical calculations using their non-dominant language. Approximate mathematical calculations appear not to be affected by language. The aim of this study is to (a) examine the relationship between brain activation during exact and approximate mathematical tasks in bilinguals using both languages, and (2) relate brain activation during mathematical tasks to brain activation during phonetic processing in both languages. We hypothesize that in both phonetic and mathematical tasks, measures of neural efficiency [Zhang et al., (2005)] will show an effect of the first versus second language. We will examine (a) the extent to which different types of calculation activate language areas, and (b) how language (number word) structures affect arithmetic processing. Two groups of bilingual adults (Chinese-English and Spanish-English) are presented with calculation problems during fMRI scans. The behavior-brain results highlight the importance of identifying the role of language, at the most basic level of phonetics, in bilingual numerical processing. Relevance of these results to a theoretical framework of language and thought will be discussed (Work funded by NSF.)
The perceptual magnet effect (PME) in L2 consonants
Authors: Hattori Kota
Published: October 2013

The perceptual magnet effect (PME) has been investigated in conjunction with L1 vowels and consonants. However, there has been a paucity of examinations of the effect in L2 speech perception. The present study used the methodology of Iverson and Kuhl [P. Iverson and P. K. Kuhl, J. Acoust. Soc. Am. 99, 1130–1140 (1996)] to examine whether Japanese speakers who have had exposure to English-speaking environments for more than 1 year exhibit the PME for /r/ and /l/. Eighteen synthetic stimuli were generated. Ten Japanese speakers and 12 American English speakers participated in an identification and rating task. Each participant engaged in ten experimental sessions (ten sessions of each of the 18 stimuli). They chose either /ra/ or /la/ and gave a rating with a 1–7 scale. They also underwent a similarity scaling task to determine the similarity of 306 pairs of the 18 stimuli with a 1–7 scale. The results indicated that, while the English speakers demonstrated the PME, some native speakers of Japanese did exhibit the PME and prefer some exemplars of English /r/ and /l/ over others. The results also revealed that other Japanese speakers exhibited reorganized perceptual space without the PME.
The influence of stress on the /d/–/t/ distinction in French
Authors: Abdelli-Beruh Nassima , Aravamudhan Radhika Aravamudhan
Published: October 2013

This study examined how monolingual French speakers produced the /d/–/t/ distinction in stressed and unstressed syllable-initial stops preceded by a voiceless phone (/s/). Syllables were embedded in sentences. Sentence durations and voicing-related differences in durations of preceding vowel, /s/, stop closure, and VOT were calculated and analyzed as a function of the stress condition separately for each speaker (stressed syllables spoken at normal speaking rate, unstressed syllables produced at normal speaking rate). Preliminary analyses reveal that the vowel and the voiceless fricative preceding the unstressed target syllables were longer than the vowel and the fricative preceding the stressed target syllables. Closure durations were also longer in the unstressed condition than in the stressed condition. However, voicing-related duration differences were not systematically affected by stress. Finally, the voicing of /s/ (/s/ before /d/) and of /d/ closures, which occurred frequently in the stress condition, occurred less frequently in the unstressed condition for most of the speakers. The perceptual consequences of such results remain to be investigated.
Use of spectral change and duration cues in vowel identification by monolingual and bilingual listeners: Evidence from confusion matrices
Authors: Rogers Catherine L. , Glasbrenner Merete M. , DeMasi Teresa
Published: October 2013

The degree to which vowel duration and time-varying spectral change cues are used in American English vowel identification was investigated for three groups of listeners: (1) monolingual American English listeners; (2) proficient Spanish-English bilinguals; and (3) less proficient Spanish-English bilinguals. Digital manipulation and high-fidelity synthesis procedures (STRAIGHT) were used to create six versions of six target items (bead, bid, bayed, bed, bad, and bod). These consisted of the unaltered whole word and five versions of the isolated vowel: (1) natural vowel—unaltered; (2) synthetic vowel with no cue alteration; (3) synthetic vowel with neutral duration; (4) synthetic vowel with flattened formants; and (5) synthetic vowel with neutral duration and flattened formants. Isolated-vowel stimuli were presented to listeners for identification in two 120-trial blocks, followed by 48 whole-word stimuli. Significant between-group differences in percent-correct performance and a significant group by listening condition interaction were found, suggesting that cue weighting may vary across groups and that some bilinguals’ phoneme representations may be less robust than those of monolinguals. Analysis of confusion matrix data will be used to further explore these hypotheses by examining patterns of confusions across group and condition and extent of individual differences across subjects within a group. [Work supported by NIH-NIDCD 1R03DC005561-01A1.]
Korean students’ repetition of English sentences mixed with noise at various speed
Authors: Yang Byunggon , Kim Eunjee
Published: October 2013

Many Korean students feel quite frustrated by native speakers’ fast talk, especially in a noisy situation. In this study, it was examined how well 33 Korean university students repeat 48 recorded English sentences at normal speed, fast speed, normal speed mixed with noise, and fast speed mixed with noise. The subject’s production was scored by the percent ratios of correctly produced words to the total words in each sentence. Results showed that overall the student group correctly repeated around 65% of all the words, while the native speakers demonstrated almost perfect performances. Students achieved 69% and 61% accuracy in their repetition of content and function words, respectively. The high-proficiency group outperformed the low-proficiency group, particularly in their repetition of function words. Student’s accuracy of repetition remarkably dropped when both the speed and noise of normal sentences were modified. The noise condition seemed to have the strongest effect on their accuracy. Finally, it was observed that the more words a stimulus sentence had, the harder the Korean students found it to repeat correctly. Those results may be helpful for English teachers to develop better teaching materials for listening skills and to offer some criteria of proficiency level in English.
Acquisition of stress and pitch accent in English–Spanish bilingual children
Authors: Kim Sahyang , Andruski Jean , Nathan Geoffrey S. , Casielles Eugenia , Work Richard
Published: October 2013

Although understanding of prosodic development is considered crucial for understanding of language acquisition in general, few studies have focused on how children develop native-like prosody in their speech production. This study will examine the acquisition of lexical stress and postlexical pitch accent in two English–Spanish bilingual children. Prosodic characteristics of English and Spanish are different in terms of frequent stress patterns (trochaic versus penultimate), phonetic realization of stress (reduced unstressed vowel versus full unstressed vowel), and frequent pitch accent types (H* versus L*+H), among others. Thus, English–Spanish bilingual children’s prosodic development may provide evidence of their awareness of language differences relatively early during language development, and illustrate the influence of markedness or input frequency in prosodic acquisition. For this study, recordings from the children’s one-word stage are used. Durations of stressed and unstressed syllables and F0 peak alignment are measured, and pitch accent types in different accentual positions (nuclear versus prenuclear) are transcribed using American English ToBI and Spanish ToBI. Prosodic development is compared across ages within each language and across languages at each age. Furthermore, the bilingual children’s productions are compared with monolingual English and Spanish parents’ productions.
New and contrastive focus in Taiwan Mandarin
Authors: Li Jia-rong
Published: October 2013

This study investigated the influence of information structure on surface acoustical parameters in Taiwan Mandarin. There were two experiments, i.e., GN and GC experiment. In GN experiment, the noun phrases placed in initial (NP1) or medial (NP2) position in a Mandarin sentence were elicited through a game. Subjects answered experimenter’s questions, e.g., ‘‘What is on pink truck’s right side?’’ according to colored pictures in a 4 by 4 matrix. New or given information was placed on either NP1 or NP2. In GC experiment, subjects corrected or confirmed expeirmenter’s description, such as Pink truck is yellow IDs right side, by placing either contrastive information on the color term and given information on noun (cg), given information on the color term and contrastive information on noun (gc), given information on both color term and noun (gg), or contrastive information on both color term and noun (cc). Results showed that the F0 range expansion and duration lengthening were observed on syllables carrying new and contrastive information. Moreover, duration lengthening is more pronunced than F0 range expansion. Furthermore, syllables with contrastive information were lengthened more than syllables with new information.
Acoustic correlates of Japanese pitch accent
Authors: Sugiyama Yukiko
Published: October 2013

Acoustic correlates of Japanese pitch accent were investigated using bimoraic/disyllabic pairs of words that are identical except for their accent patterns. For example, /hana/ ‘‘flower’’ and /hana/ ‘‘nose’’ have the same phonological shape and pitch levels (low-high) yet they differ in that ‘‘flower’’ is accented but ‘‘nose’’ is unaccented. The most notable acoustic difference between the two accent patterns is realized by the F0 of the following word when there is one. There have been debates about whether the two accent patterns are acoustically different when the following word is excluded. It has been proposed that the F0 maximum is higher, and/or the F0 movement is larger for the accented words. While previous studies used only a few pairs of words, this study tests all 20 pairs of words found by searching a computerized dictionary [Amano and Kondo (1999)] that had a relatively high word familiarity. The F0 maximum and movement were measured in the 20 pairs of words as produced by native speakers of Tokyo Japanese (males and females) in isolation and two frame sentences. Implications of their results for the nature of accent in Japanese and the perception of accent will be discussed.
The prosody of the compound words in Hong Kong Cantonese
Authors: Zee Eric
Published: October 2013

The bisyllabic, trisyllabic, and quadrisyllabic compounds in Hong Kong Cantonese were analyzed for their prosodic characteristics, including temporal structure, F0 contour, and intensity contour. Results show that the durations of the syllable-initial fricatives and the voice onset time of the aspirated stops and aspirated affricate of the component syllables vary according to the positions in the compounds in which the syllables occur. As for the unaspirated stops and affricate, they are not affected by the positions of the component syllables. The rime durations which also vary according to their positions in the compounds are longest for the final syllables to be followed by the preceding syllables in decreasing order. In the case of the quadrisyllables, the difference in rime duration between the initial and second component syllables is insignificant. On the basis of the findings, temporal models for the compounds are constructed. The F0 contours of the citation tones on the component syllables may be subject to the F0 declination effect. The shapes of the citation tones may change, but in most cases the citation forms are retained. With a few exceptions, the intensity curves for the rimes co-vary with the F0 contours.
Seabed variability and its influence on acoustic prediction uncertainty
Authors: Holland Charles W. , Calder Brian , Kraft Barbara , Mayer Larry , Goff John , Harrison Chris
Published: October 2013

Kevin LePage (Naval Research Laboratory, Washington, DC), Robert I. Odom (University of Washington, Applied Physics Laboratory), Irina Overeem, James Syvitski (University of Colorado, INSTAAR, Boulder, CO) and Lincoln Pratson (Duke University, Durham, NC). The weakest link in performance prediction for naval systems operating in coastal regions is the environmental data that drive the models. In shallow-water downward refracting environments, the seabed properties and morphology often are the controlling environmental factors. In order to address the issue of uncertainty in seabed properties, we focused on two overarching goals: (1) assess and characterize seafloor variability in shelf environments, (2) determine the impact of the seafloor variability on acoustic prediction uncertainty. Our inherently multidisciplinary approach brought marine geology/geophysics and ocean acoustics together at the intersection of geoacoustic modeling. This talk will review results from a 3-year collaboration under the ONR Capturing Uncertainty DRI. [Work supported by the Office of Naval Research.]
Sonar detection performance prediction of a moving source in an uncertain environment
Authors: Krolik Jeffrey , Varadarajan Vivek
Published: October 2013

This paper addresses the problem of passive sonar detection of a moving acoustic source when both the signal spatial wavefront and background noise field are uncertain. The classic sonar equation is derived for a stationary source-receiver geometry and known environment. For dynamic scenarios, however, array gain (AG) and transmission loss (TL) can fluctuate in time and frequency over the integration time and bandwidth used. This is caused by signal multipath group and phase velocity differences at the receiver array. Moreover, for adaptive methods, noise covariance matrix snapshot support is often limited. This paper presents methods for estimating TL and AG under these conditions from a moving source of opportunity. These estimates are then used to predict adaptive detection performance. Results for probability of detection versus signal-to-noise ratio using real horizontal array data from the Swellex-96 experiment are shown to compare favorably with theoretically predicted detection performance. [Work supported by ONR.]
Effects of uncertain geoacoustic parameters and coastal shipping densities on shipping noise directionality
Authors: Hayward Thomas J. , Heitmeyer Richard M.
Published: October 2013

The bearing-elevation directionality of low-frequency shipping noise is influenced both by the sediment geoacoustic parameters and by the coastal shipping density. This study examines the effects of geoacoustic parameter and shipping density uncertainties on noise directionality through simulations for a North Pacific site. The simulations are based in part on stochastic models of the spatial variations of geoacoustic parameters that incorporate: (1) conditional probability densities of the geoacoustic parameters given mean sediment grain size, derived from measurement compilations reported by Hamilton et al. [J. Acoust. Soc. Am. 72,1891], and (2) location-dependent probability densities of the mean grain size, derived from field measurements. [Carlson et al., U.S. Geological Survey Map MF 876]. The simulations also incorporate coastal shipping noise source uncertainties based on models of commercial fishing vessel locations and ship-radiated noise. [Wales and Heitmeyer, J. Acoust. Soc. Am. 111, 1211] The results quantify the effects of the geoacoustic and coastal shipping uncertainties on received low-frequency bearing-elevation noise directionality. Variances in the noise power at horizontal arrival due to geoacoustic uncertainties substantially exceed those associated with uncertainties in the shipping noise source distributions and levels. These results are interpreted in terms of down-slope propagation effects. [Work supported by ONR.]
Determining the sensitivity of measured acoustic quantities on variability in geophysical and oceanographic conditions
Authors: Pecknold Sean , Hines Paul , Osler John
Published: October 2013

Sonar is used to remotely investigate the underwater environment and to detect and track vessels therein, either by their own acoustic emissions or through scattering from active transmission. The acoustic signals available to an observer are a function of the transmitter’s relative position, course, and signature, and the local environment. In order to make effective use of the received acoustic signals, an observer requires a thorough understanding of the propagation and scattering characteristics of the overall underwater environment as well as the implications of those characteristics on the analysis techniques applied to the received signals. Defense R&D Canadas (DRDC) Rapid Environmental Assessment (REA) Program aims to provide a capability for accumulation and interpretation of environmental information in a tactical timeframe. A main objective of the REA program is to explore the nature of geophysical and oceanographic variability and to quantify its effect on acoutic signals. This effect is analyzed via modeling and through the use of data from the joint DRDC/NURC sea trial BASE 04 (Broadband Acoustic Sonar Experiment 2004). This trial, which took place in May and June of 2004 in the Malta Plateau and Medina Bank areas, included several experiments measuring active sonar propagation in an uncertain environment.
Object representation in echolocating bats: Recognition of targets from different orientations
Authors: DeLong Caroline M. , Bragg Rebecca , Simmons James A.
Published: October 2013

Big brown bats (Eptesicus fuscus) can discriminate among objects using wideband FM sonar sounds. Bats could perceive and represent only the acoustic dimensions of echoes (e.g., delay, frequency, amplitude), or they could use those dimensions to reconstruct object features (e.g., distance, shape, size). To investigate this question, bats were presented with a two-alternative (left/right) forced-choice sonar discrimination task. The stimuli were a one-cylinder monopole target and a two-cylinder dipole target that was presented at all aspect angles. Acoustic dimensions of the dipole echoes change depending on aspect angle. If the bats represent only acoustic dimensions, they should have difficulty selecting the dipole. If the bats represent object features, they should be able to select the dipole independent of aspect angle. Bats can select the dipole over a wide range of aspect angles, suggesting that they construct object features from echo acoustic dimensions. The bats’ error patterns may indicate the echo dimensions they use to construct object features. [Work supported by NIH and ONR.]
Bioacoustic absorption spectroscopy: The promise of classification by fish size and species
Authors: Diachok Orest , Smith Paul , Wales Stephen , Scalabrin Carla
Published: October 2013

A recently completed experiment, BAS II, was designed to test the validity of inferences of fish length from measurements of bio-alpha in frequency (250–5000 Hz)-depth (8–53 m) space. This experiment was conducted in the vicinity of sardine and anchovy spawning grounds at a 63-m-deep site where oceanic, biological, and geologic parameters were well calibrated. Classifications of absorption lines associated with 15-cm-long sardines, 11-cm-long anchovies, and 6-cm-long juvenile anchovies (recorded at night when most fish were dispersed) were consistent with trawl and historical data. Classification of an absorption line, possibly associated with juvenile sardines, was inconclusive, due to inconsistencies between trawl and historical data. Very low frequency lines may have been due to bubble cloud resonances associated with sardine schools, or larger fish which avoided sampling. The scintillation index associated with bio-alpha lines, which is hypothetically driven by the rate of change of number densities, may offer additional classification clues, since fish dynamics may be species specific. Time series measurements over a few months would permit further testing and refinement of classification methods, a prerequisite for applications oriented BAS-based measurement systems, including observatories. [Work was supported by ONR.]
Passive acoustic monitoring of biological activity on coral reefs and in nearby waters
Authors: Lammers Marc O. , Mooney T. Aran , Brainard Russell E. , Au Whitlow W. L.
Published: October 2013

Monitoring the changing state of coral reef habitats is a challenging task that is exacerbated when the reefs in question are in remote locations. Physical sensors provide a wide range of measurements of local environmental variables, but do not give an indication of biological activity. The preliminary findings of an effort to use the ambient sound field as a means of characterizing and monitoring biological activity on coral reefs and surrounding waters are reported. Moored recording systems were developed to sample the sound field of reefs on Oahu, Hawaii for 1-min periods, at 30-min intervals, for 10 days at a time. Snapping shrimp produce the dominant acoustic energy on the reefs examined and exhibit clear diel acoustic trends. Peaks in activity consistently occur during crepuscular periods. At frequencies below 2 kHz, many fish sounds occur, which also exhibit distinct temporal variability. Cetacean sounds are also common, indicating the occurrence of an apex predator in the area. Many sounds can be detected automatically, making the examination of the sound field an efficient means of tracking acoustically active species. The results indicate that acoustic monitoring may be an effective means of tracking biological activity at locations where traditional surveys are impractical.
Model-based passive acoustic tracking of sperm whale foraging behavior in the Gulf of Alaska
Authors: Tiemann Christopher , Thode Aaron , Straley Jan , Folkert Kendall , O’Connell Victoria
Published: October 2013

In 2004, the Southeast Alaska Sperm Whale Avoidance Project (SEASWAP) introduced the use of passive acoustics to help monitor the behavior of sperm whales depredating longline fishing operations. Acoustic data from autonomous recorders mounted on longlines provide the opportunity to demonstrate a tracking algorithm based on acoustic propagation modeling while providing insight into whales’ foraging behavior. With knowledge of azimuthally dependent bathymetry, a 3D track of whale motion can be obtained using data from just one hydrophone by exploiting multipath arrival information from recorded sperm whale clicks. The evolution of multipath arrival patterns is matched to range-, depth-, and azimuth-dependent modeled arrival patterns to generate an estimate of whale motion. This technique does not require acoustic ray identification (i.e., direct path, surface reflected, etc.) while still utilizing individual ray arrival information, and it can also account for all waveguide propagation physics such as interaction with range-dependent bathymetry and ray refraction.
Ophthalmic imaging with a 40-MHz annular array
Authors: Ketterling Jeffrey A. , Ramachandran Sarayu , Silverman Ronald H. , Aristizábal Orlando
Published: October 2013

High-frequency annular arrays provide a means for improving the depth of field versus single-element transducers. An annular array with five equal-area rings has been designed and an experimental system has been assembled to test it. The transducer is fabricated from a 9-μm polyvinylidene fluoride (PVDF) membrane bonded to a copper-clad polyimide film. The transducer has a total aperture of 6 mm, a geometric focus of 12 mm, and a nominal center frequency of 40 MHz with a 6-dB fractional bandwidth of 33%. The device is pressed into a spherically curved geometry and then backfilled with epoxy. Radio-frequency data were acquired for all 25 transmit/receive ring pairs, and then postprocessed with a synthetic focusing algorithm to improve the image depth of field (DOF). The resulting processed data improved DOF by a factor of 6 compared to a single-element transducer of the same total aperture and geometric focus. To test the system, rf data were acquired from excised bovine eyes, human cadaver eyes, and anesthetized rabbits. The tests revealed enhanced resolution away from the geometric focus and a more uniform image brightness than can be achieved with high-frequency, single-element devices. [This work was supported by NIH Grant EY014371.]
Multiplanar angular spectrum approach for fast simulations of ultrasound therapy arrays
Authors: Zeng Xiaozheng , McGough Robert
Published: October 2013

Pressure field modeling with ultrasound phased arrays designed for thermal therapy is extremely time-consuming due to the large computational grids required and because each array contains a large number of elements. The angular spectrum approach (ASA) computes wave propagation in parallel planes with a two-dimensional fast Fourier transform in considerably less time than point-by-point direct integral methods. The conventional ASA, which performs well with planar and small focused radiators, encounters numerical problems in simulations of large phased arrays. These errors are caused in part by the narrowing of the beam in the focal region, which produces a significant increase in the spatial frequency content. The numerical errors are reduced with the inclusion of additional source planes within the computational domain. These are distributed such that the distance between adjacent source planes is small near the focal zone, and the spacing between source planes grows progressively larger as the distance from the focus increases. This approach, which compensates for the error produced by spatial aliasing, reduces the computation time required for simulations of large ultrasound phased arrays while maintaining the necessary accuracy for thermal therapy simulations. [Supported in part by NIH Grant R01-CA093669.]
Polyvinylidene fluoride (PVDF) vibration sensor for stethoscope and contact microphones
Authors: Toda Minoru , Thompson Mitchell
Published: October 2013

This paper describes a new type of contact vibration sensor made by bonding piezoelectric PVDF film to a curved frame structure. The concave surface of the film is bonded to a rubber piece having a front contact face. Vibration is transmitted from this face through the rubber to the surface of the PVDF film. Pressure normal to the surface of the film is converted to circumferential strain, and an electric field is induced by the piezoelectric effect. The frequency response of the device was measured using an accelerometer mounted between the rubber face and a rigid vibration exciter plate. Sensitivity (voltage per unit displacement) was deduced from the device output and measured acceleration. The sensitivity was flat from 16 Hz to 3 kHz, peaking at 6 kHz due to a structural resonance. Calculations predicting performance against human tissue (stethoscope or contact microphone) show results similar to data measured against the metal vibrator. This implies that an accelerometer can be used for calibrating a stethoscope or contact microphone. The observed arterial pulse waveform showed more low-frequency content than a conventional electronic stethoscope.
The good, the bad, and the bogus in acoustical patents
Authors: Augspurger George L.
Published: October 2013

Patent reviews published in the Journal of the Acoustical Society of America are intended to provide useful information from the standpoint of an informed layman. From that perspective at least 50% of acoustical patents are superfluous and a good many are outright fraudulent. Why do we see so many patents that arguably should never have been issued? Part of the answer lies in common misconceptions about the purpose of a U.S. patent and the protection it provides. Additional confusion arises from the common strategy of writing patent text to obfuscate rather than enlighten. Examples of junk patents, vanity patents, and bogus patents will be presented to illustrate current trends in the patent process.
A recent U.S. patent process for a musical instrument
Authors: Baecker James I.
Published: October 2013

The ins and outs of going from a novel musical instrument concept to issuance of a U.S. patent. The technical work performed included the development of a musical instrument based on space-frame body construction and a definition of the instrument body’s resonance characteristics. The result required a description of the invention and communication with the patent attorney and conveying a correct perception of the invention to the U.S. Patent Office. This presentation describes several technical, practical, legal, and commercial issues encountered during the patent process by the inventors and their business entity. On 7 September 2004, U.S. Patent No. 6,787,688 for a musical instrument was issued and assigned by the inventors to Harmos Music, Ltd.
Studies of the effect of aging of ‘‘quiet’’ pavements on tire/pavement noise
Authors: Reyff James A. , Donavan Paul
Published: October 2013

One of the issues with using quieter pavements to abate traffic noise is their continued acoustic performance over the life cycle of the surface. Aging effects can be assessed in two manners: (1) long term monitoring of the noise performance of an individual section of roadway; (2) measurement of multiple sections of pavement of the same construction, but different ages. Long term monitoring of Interstate 80 near Davis (I-80 Davis) began in 1998, just prior to the placement of a dense graded leveling course and open graded asphalt overlay. The pavement surface is now approaching 7 years old and continues to show a traffic noise reduction of about 5 dBA over the existing condition. As support of the Arizona Quiet Pavement Program (QPPP), similarly constructed sections of asphalt rubber friction course (ARFC) on Arizona’s interstate highways were measured for tire/pavement performance using the close proximity (CPX) method and the on-board sound intensity method. The construction dates for the pavements ranged from 1988 to 1999. The total range in noise level was 7 dB with some indication of degrading performance with age.
Overview of the Arizona Quiet Pavement Program
Authors: Donavan Paul , Scofield Larry
Published: October 2013

The Arizona Quiet Pavement Pilot Program (QP3) was initially implemented to reduce highway related traffic noise by overlaying most of the Phoenix metropolitan area Portland cement concrete pavement with a one inch thick asphalt rubber friction coarse. With FHWA support, this program represents the first time that pavement surface type has been allowed as a noise mitigation strategy on federally funded projects. As a condition of using pavement type as a noise mitigation strategy, ADOT developed a ten-year, $3.8 million research program to evaluate the noise reduction performance over time. Historically, pavement surface type was not considered a permanent solution. As a result, the research program was designed to specifically address this issue. Noise performance is being evaluated through three means: (1) conventional roadside testing within the roadway corridor (e.g., far field measurements within the right-of-way); (2) the use of near field measurements, both close proximity (CPX) and sound intensity (SI); and (3) far field measurements obtained beyond the noise barriers within the surrounding neighborhoods. This paper provides an overview of the program development, presents the research conducted to support the decision to overlay the urban freeway, and the status of current research.
Reduction of traffic and tire/pavement noise: 1st year results of the Arizona Quiet Pavement Program—Site III
Authors: Reyff James A. , Donavan Paul
Published: October 2013

The Arizona Quiet Pavement Pilot Program overlaid major freeway segments in the Phoenix area with an Asphalt Rubber Friction Course (ARFC). The overlay was placed on various Portland Cement Concrete Pavement (PCCP) textures. Traffic noise reductions were evaluated by performing wayside traffic noise measurements and tire/pavement source level measurements. First year results for three different study sites are presented in this paper. Depending on the texture of the initial PCCP and microphone locations, reductions of up to 12 dBA in wayside traffic noise levels were measured. Similar reductions of tire/pavement source levels were measured. Results of the two methods are compared. Traffic conditions monitored during the measurements were modeled using the Federal Highway Administration’s Traffic Noise Model (TNM 2.5) to compare modeled levels to those measured for PCCP and AFRC overlay conditions. The model under predicted levels for PCCP conditions and over predicted levels for AFRC conditions. The magnitude of under or over prediction varied with distance. The effect of propagation was examined and was aided by simultaneous measurements of wind conditions made by Arizona State University. TNM 2.5 was used to identify sound wall heights that were equivalent to the traffic noise reductions provided by the AFRC overlay.