bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptual cues to English lexical stress: Comparison between native speakers and Mandarin second language learners.
Authors: Lai Yuwen , Sereno Joan
Published: October 2013

The present study investigates the role of F0, duration, and vowel quality in English lexical stress perception by second language learners with a tonal L1. Mandarin speakers learning English as a second language (advanced learners, n=25; beginning learners n=25) were compared to a control group of native English speakers (n=25). Resynthesized disyllabic nonwords (dada) were presented in a stress localization task. Simultaneously manipulating five different F0 ratios (ratio of maximum fundamental frequency values of the first and second vowels) and five different duration ratios (ratio of duration values of the first and second vowels), stimuli were synthesized based on acoustic measurements from a previous study [Y. Lai and J. Sereno, J. Acoust. Soc. Am. 121, 3071 (2007)]. Both full-vowel and reduced-vowel stimuli were used. The results indicated that full vowels most often attracted stress across all three listener groups. More interesting, beginning second language listeners relied mainly on duration cues to determine the stressed syllables and advanced listeners focused more on F0 cues, while native listeners made use of both cues. The findings will be discussed in terms of the similarities and differences between the prosodic systems of Mandarin and English.
Ocean surface degradation of shallow water acoustic communication.
Authors: Edelmann Geoffrey , Anderson Shaun , Gendron Paul
Published: October 2013

The accurate prediction of underwater acoustic communication system performance at high frequencies is essential to system risk mitigation prior to deployment. The deterioration of acoustic coherence by ocean surface dynamics will be predicted via three dimensional (3-D) ray tracing with the inclusion of interaction with a realistic dynamic ocean surface. Acoustic communication performance limits at high frequencies for most fixed platform systems are dominated by multipath interaction with the spectrally rich heaving ocean. The high-fidelity Wave-watch III surface spectra model is used here with a wave-number integration approach for surface time series modeling. A fully 3-D ray tracing model is used to model the propagation of sound under a dynamic surface boundary at the time and spatial scales that dominate coherence degrading effects for underwater acoustic communications. The proposed method will serve the rapid development of operating regimes for high-frequency underwater acoustic communication systems. Proposed applications include distributed underwater sensor networks and persistent deployable low-cost systems that meet a wide range of underwater sensing needs. This work seeks to solve problems in deploying advanced communication systems by predicting the degradation of signals due to ocean variability and automatically selecting appropriate signaling rates, schemes, and constants. [This work was supported by ONR.]
Acoustic monitoring of severe weather in the Northeast Pacific Ocean.
Authors: Nystuen Jeffrey , Vagle Svein
Published: October 2013

Wind and rainfall are the principal physical processes responsible for the production of high-frequency (1–50 kHz) ambient sound in the ocean. The primary source of the sound is the resonant ringing of individual bubbles created during wave breaking and raindrop splashes. Larger bubbles (>300 μm diameter) quickly return to the surface, while smaller bubbles can be mixed downward at several meters. During severe weather a layer of smaller ambient bubble forms and effectively absorbs higher-frequency (>10 kHz) sound. These processes are revealed in a two-year record of ambient sound recorded from a subsurface mooring at 50N, 145W in the NE Pacific Ocean as part of the Canadian SOLAS program. The passive acoustic signal of wind, rain, and ambient bubble clouds are compared to the subsurface mooring data, including data from an upward looking 200 kHz active sonar and a 300 kHz ADCP. The acoustic signatures of light, moderate, and heavy rainfall are superimposed on the signature of high wind, demonstrating rainfall detection even in the presence of high wind. [Work supported by ONR, Fisheries and Oceans Canada, and the Canadian CFCAS NSERC.]
Bat-inspired distance measurement using phase information.
Authors: Assous Said , Jackson Peter , Hopper Clare , Gunn David , Rees John , Lovell Mike
Published: October 2013

This paper shows the use of phase measurement to estimate the distance to a target. Inspiration for this work comes from the observation that bats have been shown to have exceptional resolution with regard to target detection when searching during flight. Au and Simmons [“Echolocation in dolphins and bats,” Phys. Today 45(7), 40–45 (2007)] concluded bats with a center frequency of about 80 kHz (i.e., 4-mm wavelength), and 40-kHz bandwidth can have a resolution of distance in air approaching 20 μm. For this frequency, we see that the resolution achieved by the bat is about 200 times better than λ/2 (i.e., 2 mm at this frequency), which is usually used as a guide for resolution for analog systems. Moreover, Au and Simmons show, using time-frequency analysis, that there are essentially two frequencies present at any particular time within a single bat pulse. Considering this use of two frequencies we may infer a distance. A new bat-inspired algorithm is presented. This is based on phase measurement and, when applied to underwater acoustics, shows that a resolution of 1/50 of the wavelength can be achieved in practice.
Contrast models and classification of active sonar signals.
Authors: Gaumond Charles F. , Jemmott Colin W. , Brock Derek
Published: October 2013

New features and algorithms are derived from human perception to improve the automation of active sonar signal classification. Data from human subject research on the perceived similarity of sound pairs can be assembled in the form of a dissimilarity matrix. A dissimilarity matrix can be analyzed in many ways, two of which are multidimensional scaling (MDS) and additive clustering (AC). Different underlying perception models can be inferred from each analysis technique: a feature vector space for MDS and a contrast model for AC. The relevance of each technique to the dissimilarity data is inferred from the quantification of model complexity to the measure of fitting the original data [D. J. Navarro and M. D. Lee, “Common and distinctive features in stimulus similarity,” Psychon. Bull. Rev. 11, pp. 961–974 (2004)]. An experimental dissimilarity matrix is shown and analyzed using MDS and AC. Potential features for each case are shown from singular value decomposition of various signal representations. Signal processing implications of real valued features in the contrast model and alternative implementation are discussed. [The authors gratefully acknowledge conversations with and results from Dr. Jason Summers. Work supported by the Office of Naval Research.]
A data fusion and multiple ping method for improving the resolution of low-power acoustic and seismic sensing.
Authors: Apartsin Alexander , Intrator Nathan
Published: October 2013

Biological research has shown that some mammals use low-power seismic pulses for underground communications and navigation. For instance, the blind mole rat bangs its head against the walls of its underground tunnel to produce seismic signals. It has been demonstrated that this animal builds a three-dimensional map of the environment by collecting and analyzing returned responses. This behavior enables the mole rat to avoid obstacles and voids while it digs its tunnels. Being able to use low-power signals for accurate remote sensing under low signal to noise ratio (15–25 dB) conditions has some important applications (e.g., underground installment detection). A practically used method for coping with noise is based on repeated transmission of identical pulses and averaging the peak value of autocorrelation function from multiple measurements. Our research suggests that by carefully selecting a pulse family and a fusion method of multiple measurements, one can significantly improve sensing resolution. In particular, our simulation results show that employing robust statistics fusion method and by producing sonar pings with a shifting phase, the average error rate of travel time estimates can be reduced by about 30%.
Perth-Bermuda (1960) revisited global scale acoustic propagation.
Authors: Heaney Kevin D. , Murray James J.
Published: October 2013

A recent paper in Geophysical Research Letter [Dushaw, Geophys. Res. Lett. 35, L08601 (2008)] commented on the Perth-Bermuda Sound Propagation Experiment (1960): An Adiabatic Mode Interpretation JASA 95, November 1991, by Kevin D. Heaney, William S. Kuperman, and B. E. McDonald. Dushaw raises questions about the validity of the approach and conclusions of Heaney et al. In particular, the validity of the adiabatic mode assumption for long-range propagation in the presence of internal wave scattering and seafloor interaction is challenged. Dushaw finds no other explanation for the observed double pulse arrival in the original 1960 experiment. The approach and conclusions of Heaney et al. will be presented. The range of validity of the adiabatic mode approximation in global scale acoustics will be addressed. The original computations of Heaney et al. were for a single mode at 10 Hz due to the computational power available at the time. Broadband results (10–50 Hz) using multiple modes summed coherently will be presented.
Modeling the three-dimensional field of a seismic airgun array and comparison to 2003 measured data.
Authors: Tashmukhambetov Arslan M. , Sidorovskaia Natalia A. , Ioup George E. , Ioup Juliette W.
Published: October 2013

The full three-dimensional field of a seismic airgun array is modeled using an enhanced parabolic equation run on a parallel cluster computer system, which is part of the Louisiana Optical Network Initiative network cluster. Source signatures are calculated using GUNDALF and NUCLEUS softwares. The calculated results are compared to available measurements collected in Green Canyon in the northern Gulf of Mexico in 2003. Three-dimensional maps showing angular variation (both emission and azimuthal angles) and range dependence are generated, which show peak pressures, sound exposure levels, total shot energy spectra, and one-third octave band analyses. [Research supported by the International Association of Oil and Gas Producers and the International Association of Geophysical Contractors.]
An online ear training program designed for students, acousticians, and architects
Authors: Kamiya Nozomi , Xiang Ning , Kleiner Mendel
Published: October 2013

As part of a continuing research initiative at the Program in Architectural Acoustics at Rensselaer Polytechnic Institute, an online ear training program has been designed and implemented for scholars active in architectural acoustics, as well as professional acousticians and architects. The project aims to provide users the opportunity to learn to evaluate selected acoustical parameters without the employment of measurement equipment. The author believes that this training program will be indispensable for those who seek careers in fields related to acoustics for such skills are currently considered to be obtainable through professional experience in the field alone. The program was created using Macromedia Flash animations to develop an interactive training environment. Features such as user identification and an animated user interface create a personalized and entertaining experience while a score tracking system and high score table encourage friendly competition amongst users. As a result, users are compelled to return for successive training sessions which promote long-term growth and learning. Basic requirements for participation include an installed version of the Flash plug-in, an internet-enabled computer, and a pair of headphones.
Speech intelligibility of lecture halls
Authors: Ronsse Lauren
Published: October 2013

For this project, different large lecture halls were analyzed using various speech intelligibility measurement techniques. The goal was to determine how well these measurements correlate with each other and convey speech intelligibility. Objective speech intelligibility and other related acoustical measurements were made throughout each hall at varying distances from the speaker. These measurements were repeated in each hall in a standardized manner, allowing the results from the different halls to be compared effectively. These objective measurements were related to the subjective analysis of the hall to determine which measurements indicate an appropriate speech intelligibility level for that space. Background mechanical system noise was introduced into some of the halls to determine the effect on speech intelligibility. Some of the halls tested were modeled in an architectural acoustics computer program to determine how well the actual measurements correlate with the predicted measurements. Measurement techniques and results of the study will be presented.
Perceptual acoustics in the Mapparium
Authors: Hartmann William M. , Colburn H. Steven , Kidd Gerald
Published: October 2013

The Mapparium is a hollow, stained-glass globe, 30 ft. in diameter, at the Mary Baker Eddy Library in Boston. It allows visitors to see the continents of the world from the perspective of an observer inside the Earth. The ears of a visitor walking across the glass bridge traverse a diameter in the equatorial plane. The acoustical properties of this space are of secondary importance, but they are so remarkable that they amaze everyone who experiences them. Extensive listening and recording experiments within the Mapparium (prior to the renovations of 2002) revealed some of the acoustical effects in detail, with source and receiver points near the bridge diameter. Among the effects are the following: anomalous broadband point-to-point amplitude transfer functions with maxima (whispering gallery) and spatially compact minima; localization illusions wherein a source on the listener’s left is heard on the right, or high- and low-frequency parts of a sound are localized differently, or sound images change in elevation as the listener walks; spatially compact regions of flutter echo; and spatially unstable reflections of one’s own voice. [Work facilitated by the Mary Baker Eddy Library for the Betterment of Humanity.]
Interference risk and dynamic shifts in calling in the gray treefrog
Authors: Schwartz Joshua
Published: October 2013

Male gray treefrogs call to attract females under challenging acoustic conditions. With increases in chorus density, background noise levels and the chance that male calls will be overlapped increase. Call overlap may jeopardize the probability of mating because females prefer advertisement calls in which the internal pulse structure of calls is not obscured to those that are overlapped by other calls. With increases in the level of acoustic stimulation, males lengthen the duration of their calls but simultaneously reduce call rate such that pulse effort changes little. The interference risk hypothesis was tested, which proposes that males change their calling in a fashion that insures that, on average, there will be a sufficient number of pulses and interpulse intervals clear of acoustic interference per call to attract a female. However, a series of female choice experiments employing call alternatives of different durations, rates, intensity levels and degrees of call overlap refuted this hypothesis. Results leave open the possibilities that the dynamic shift in the two components of pulse effort are related to the problem of call detection in a noisy environment or are responses by males to the perceived threat of competition for females. [Work supported by NSF.]
Signal timing by the gray treefrog, Hyla chrysoscelis: Responses to conspecific and heterospecific advertisement calls
Authors: Marshall Vincent
Published: October 2013

Breeding choruses often consist of multiple species sharing the same communication channel. Whether and how a signaler adjusts the timing of its signals, an often important predictor of receiver response, may therefore depend on the species identity of its neighbor. How males of the gray treefrog, Hyla chrysoscelis, adjusted advertisement call timing towards the calls of conspecifics and those of the closely related, syntopic species, H. versicolor, was examined. During interactions between calling males, calls were timed such that there was little signal overlap regardless of whether the neighbor was conspecific or heterospecific. In response to playbacks of conspecific and heterospecific advertisement calls, males generally avoided producing calls during either stimulus type, and instead produced them during the silent gaps between stimuli. There were, however, significant differences in the latencies of response to conspecific and heterospecific signals. Males produced calls with shorter latencies after the heterospecific calls, which resulted in their often rapid placement within the silent intervals between stimuli. In contrast, calls produced after conspecific stimuli almost always had a distinct gap after the stimulus ended. These results are discussed in light of hypotheses for the function of adjustments in the timing of acoustic sexual signals.
The cocktail party problem: What is it? How can it be solved? And why should students of bioacoustics study it?
Authors: Bee Mark A.
Published: October 2013

Auditory scene analysis refers to mechanisms that parse a composite acoustic waveform into perceptually distinct auditory objects or streams that correspond to distinct sound sources in the environment. A familiar and well-studied example of a difficult auditory scene analysis task is the cocktail party problem, which refers to the difficulty we have perceiving speech in noisy social environments comprised of multiple people talking simultaneously. Students of human hearing and computer engineering study auditory scene analysis, in part, because people with hearing impairments and computer algorithms for speech recognition do a poor job of solving the cocktail party problem compared to people with normal hearing. Of course, the cocktail party problem is not unique to humans. The animal behavior literature provides numerous examples of cocktail-party-like social environments for animal acoustic communication (e.g., choruses, roosts, colonies, creches). Compared to previous work on humans, however, students of animal bioacoustics have devoted little attention to how animals that signal in groups or networks solve their own cocktail party problems. This talk will briefly review some issues in auditory scene analysis relevant to the study of animal acoustic communication and present the case for why these issues deserve further study by students of bioacoustics.
The relevance of bubbles in clinical high-intensity focused ultrasound treatments
Authors: ter Haar Gail
Published: October 2013

Until recently there has been a dichotomy of opinion as to the utility of bubbles in clinical HIFU treatments. On the one hand uncontrolled acoustic cavitation can lead to lesions of unpredictable shape, size, and position, while on the other, lesions containing bubbles are visible on conventional B-mode ultrasound images, and clinically are generally regarded as being indicative of tissue destruction. In some HIFU treatments of cancer, therefore, the ultrasound exposure levels are increased until bright ups are seen on the real time ultrasound scan of the target volume. It is now known that, in the presence of acoustic cavitation, the rate of heating is considerably enhanced, and investigations are under way to establish whether controlled cavitation induction can be used to speed up clinical HIFU treatments. When temperatures in excess of 100°C are achieved in tissue, tissue water boiling will occur. This too will result in enhanced scatter in the ultrasound image. Boiling will also result in tissue destruction. The clinical implications of bubble activity will be reviewed in this paper.
Bubble nucleation, growth and dissolution in soft tissue
Authors: Church Charles C.
Published: October 2013

Vapor bubbles of sufficient size to serve as cavitation nuclei may form spontaneously in tissue in regions of very low interfacial tension. In the absence of an acoustic wave or other mechanical stress, such nuclei will quickly dissolve and disappear from the medium. Under the influence of an acoustic wave, however, these microbubbles may grow to many times their initial size and then collapse violently, a process known as inertial cavitation. The in vivo energetics of the nucleation process are treated by assuming tissue to be a homogeneous fluid, while the initial dynamics of nucleated bubbles are modeled by treating tissue as an isotropic, viscoelastic solid. It is shown that the rate of nucleation-cavitation events is highly sensitive to the instantaneous tissue temperature and moderately sensitive to the rarefactional pressure. The effect of tissue elasticity is to increase the threshold pressure for inertial cavitation and decrease the rate of rectified diffusion relative to bubbles in water. Finally, the increased rigidity of denatured soft tissue enhances the persistence of gas/vapor bubbles following the acoustic pulse.
A model for irregular lesion formation including cavitation bubbles and boiling
Authors: Wu Tianming , Farny Caleb H. , Roy Ronald A. , Holt R Glynn
Published: October 2013

Nonlinear propagation and scattering of incident sound due to the presence of gas/vapor bodies and temperature-dependent sound speed and acoustic absorption have been found to contribute to irregular lesion formation during high-intensity focused ultrasound therapy. The appearance and importance of these mechanisms are dependent on the intensity of insonating sound and the medium properties. In the regime where the focal pressure is slightly above the cavitation threshold and the medium possesses sufficient nuclei, photographic observations and model simulations for tissue phantoms reveal that tadpole lesions start to develop prior to large-scale boiling; however, enhanced heating from inertial cavitation greatly accelerates the progression to boiling. The relative time scales for cavitation-triggered boiling and bubble dissolution are studied in order to yield insight on how to control pulse-mode HIFU insonation in order to either avoid bubble behavior outright or utilize cavitation and boiling to promote therapy. [Work supported by the Dept. of the Army (Award No. DAMD17-02-2-0014) and the Center for Subsurface Sensing and Imaging Systems (NSF ERC Award No. EEC-9986821).]
The dependence of temperature rise and cavitation dose on acoustic pressure during high-intensity focused ultrasound (HIFU) application
Authors: Farny Caleb H. , Wu Tianming , Holt R. Glynn , Roy Ronald A.
Published: October 2013

Given sufficient nuclei, inertial cavitation can greatly enhance heating rates during HIFU application. In the absence of bubble shielding effects, one might assume that increasing the driving pressure amplitude will serve to enhance both the temperature elevation and the amount of cavitation activity. Here we report on measurements in agar-graphite phantoms that show that during HIFU application, cavitation dose and temperature rise do increase with increasing pressure but only to a point where there is a measurable decrease in the 2.5–3-MPa range followed by further increase with higher pressures. This behavior can be predicted using single-bubble dynamics with allowed equilibrium bubble sizes that are consistent with waterlike viscosity values for an effective Newtonian fluid host [see Yang et al., J. Acoust. Soc. Am. 116, 3423–3431 (2004) for details]. These results can serve to help guide an optimal pressure as well as develop a further understanding of the bubble parameters and energy dissipation mechanisms involved in HIFU. [Work supported by the Dept. of the Army (Award No. DAMD17-02-2-0014) and the Center for Subsurface Sensing and Imaging Systems (NSF ERC Award No. EEC-9986821).]
Focused ultrasound-induced opening of the blood-brain barrier in mice
Authors: Choi James J. , Pernot Mathieu , Small Scott A. , Konofagou Elisa E.
Published: October 2013

The feasibility of blood-brain barrier (BBB) opening in the hippocampus of mice using transcranial focused ultrasound (FUS) was investigated on simulations and in vivo experiments. A micro-CT scan of an excised mouse skull was performed (resolution: 0.01 mm) and mappings of porosity, speed of sound, density, and attenuation were calculated. A 1.5-MHz wave propagating through the skull mappings was simulated, revealing a well-formed beam, minimal attenuation, and minute focus displacement. These results were verified with needle hydrophone measurements through five excised mouse skulls. In experiments in vivo, three mice were intravenously injected with a bolus of 0.01-mL ultrasound contrast agents (Optison) and the brains were sonicated transcranially. Ultrasound sonications (frequency: 1.5 MHz; burst length: 20 ms; duty cycle: 20%; acoustic pressure range: 2.0 to 2.7 MPa) were applied five times for 30 s per shot with a 30-s delay between shots. High-resolution (9.4 tesla), contrast-enhanced MR imaging revealed BBB opening and slow permeation of gadolinium from the posterior cerebral artery (10-min postinjection) through the surrounding tissue (35-min postinjection) and to the entire left hippocampus (95-min postinjection). These results demonstrate the feasibility of localized, noninvasive BBB opening in mice using transcranial FUS for potential precise drug delivery.
Room-acoustic energy decay analysis and acoustic landmine detection within Bayesian framework
Authors: Xiang Ning , Jasa Tomislav
Published: October 2013

Model-based signal processing has been applied in sound energy decay analysis in enclosures for estimation of reverberation times [N. Xiang, J. Acoust. Soc. Am. 98, 2112–2121 (1995)] and estimation of diverse decay times to quantify sound energy decay in coupled spaces. Recent works using Bayesian approaches have demonstrated success in this application [Xiang et al., J. Acoust. Soc. Am. 110, 1415–1424 (2001); 113, 2685–2697 (2003); 117, 3705–3715 (2005)]. Similar approaches have also been applied in acoustic landmine detection [Xiang & Sabatier, J. Acoust. Soc. Am. 113, 1333–1341 (2003)] for target detection and target localization. Respective models have been developed for each application in order to apply model-based Bayesian approaches in two different acoustical regimes. Using experimentally measured field data, this paper demonstrates an example of data analysis solutions developed for the room-acoustics application which can also be applied to another physical regime: acoustic landmine detection.
Recent developments in ambient noise processing
Authors: Siderius Martin , Porter Michael B. , Harrison Chris H.
Published: October 2013

For many sonar applications noise is an annoyance and great effort is expended to minimize its impact. It may be surprising that ocean acoustic noise can itself be used in ways that rival or surpass complex sonar systems with controlled sound sources. Although ocean noise has been studied for many years, recent developments have led to exciting new ways to exploit the noise field for practical applications. In particular, by cross correlating the noise measured on two sensors one can recover a reasonable estimate of the impulse response between the sensors. This coherent processing was first demonstrated for sensors horizontally separated, however, it was also recently applied to vertically separated sensors. The vertical configuration leads to a type of passive fathometer that not only determines water depth but also reveals the seabed layering. A second development uses beamforming on the incoherent noise field to estimate bottom reflection loss. Combining these coherent and incoherent techniques leads to powerful ways to determine the properties of the seabed. This presentation will provide a summary of these recent developments and will show how these are combined for profiling the geoacoustics of the seabed using noise. Examples will be shown using both measured and simulated data.
High frequency noise modeling: Dependence on application
Authors: Harrison Chris H.
Published: October 2013

It is tempting to think that one could build a practical, general purpose noise model suitable for high or low frequencies and any application. For many signal processing and system applications this may be true, and one could incorporate directionality and spatial coherence. Recent developments in the use of wind-and sea-surface noise to determine geoacoustic properties by cross correlating hydrophone signals or beams demonstrate the need for more detail. The correlation peaks that correspond to absolute distances or ranges clearly require (frequency domain) coherence in any simulation. In contrast, layer information derived from angular reflection loss measurements by spectral factorization does not require coherence since it originates from an angular power spectrum. In both these cases the assumption of a uniform sheet of incoherent sources is adequate. However, to investigate the temporal statistics in either case, for instance to estimate averaging times, requires a fairly detailed model of the surface wave spatial field. Thus, the noise model is very much application dependent. These mechanisms and effects will be discussed in the context of experimental data.
Robustness and constraints of high-frequency ambient noise inversion for sonar performance estimation
Authors: Arvelo Juan I.
Published: October 2013

Perhaps the most dominant source of error in sonar performance estimation in shallow waters is the geoacoustic description of the seafloor. Various investigators have studied the possible use of ambient noise to infer some key parameters such as the critical angle, geoacoustic properties, or bottom loss. Most operational sonar performance models and tactical decision aids require the bottom loss as a function of grazing angles and frequency to describe the reflected acoustic energy off the ocean floor. Harrison and Simons [Harrison & Simons, ‘‘Geoacoustics inversion of ambient noise: A simple method,’’ J. Acoust. Soc. Am. 112, 1377 (2002)] described a simple measurement approach to infer the bottom loss from ambient noise measurement on a vertical line array. This approach is well suited as an environmental measurement approach during naval operations. The robustness and operational constraints of this measurement approach are quantified using a high-frequency ambient noise model that accounts for wind, shipping, and thermal noise [Ferat & Arvelo, ‘‘Mid-Frequency Ambient Noise Directivity And Array Response in Range-Dependent Environments,’’ High-frequency Ocean Acoustics Conference Proceedings, 2004)]. The effects of array tilt, nearby shipping noise, water absorption, thermal noise, surface-noise dipole pattern, and array beam response on sonar performance estimation are demonstrated. Mitigating factors to maximize estimated bottom loss accuracy will also be outlined.
Design parameters for impact sound insulation in lightweight wood and steel structures
Authors: LoVerde John J. , Dong David W.
Published: October 2013

One of the challenges in the acoustical design of multifamily wood and steel joist buildings is reducing low-frequency sounds from footfalls on both carpeted and isolated hard-surfaced floors. Theoretical calculations and field-testing experience indicate that low-frequency impact noise in lightweight structures is clearly audible, and that traditional isolation methods do not reduce low-frequency impact noise to inaudibility [Blazier and DuPree, J. Acoust. Soc. Am. 96, 1521–1532 (1994)]. We report numerous measurements performed on wood-frame assemblies in the United States using the tapping machine method as defined in ASTM E1007. The impact sound-pressure level was measured down to the 20-Hz third-octave band, instead of 100 Hz as described in the standards. Representative case studies will be presented showing the effect of changes in construction on occupant complaints. The results indicate that the unweighted level in the 50–80 Hz third-octave bands correlates much better with occupant reaction than any of the other metrics [LoVerde and Dong, J. Acoust. Soc. Am. 112, 2201 (2002); LoVerde and Dong, INCE Inter-Noise 2004 Proceedings, 167 (2004)]. Factors in the design of successful lightweight floor/ceiling assemblies, including structural design parameters, shall be presented along with corresponding acoustical performance and subjective reactions.
Old mills, new condos; sound isolation in mill building conversion projects
Authors: Markham Benjamin , Sacks Jonah , Su Rose Mary
Published: October 2013

Up and down the New England Coast, century-old mill buildings are being converted into condominium and apartment buildings amidst one of the biggest housing booms in recent memory. While the inherent acoustical conflicts in multi-family dwelling are not new (oft-cited HUD guidelines are approaching their 40th birthday), the flood of mill conversions is bringing to light a number of new constructions that architects use to chop former factories into discrete living spaces. This paper will present field-collected data and case studies that illustrate some of the problems and common pitfalls associated with mill building conversion projects. Among the construction details discussed include exposed timber ceilings that run continuously across gypsum board partitions, the creative reuse of existing brick walls, and some acoustical properties of wood deck construction common to many mill buildings.
Noise in a multifamily housing area in Mexico City
Authors: Beristain Sergio
Published: October 2013

Noise in a multifamily housing site is complex and hard to handle due to economic, cultural, educational, income, and many other reasons. The site studied here is surrounded by commercial and services areas, which increases the noise problem. Most of the complaints do not go too far due to lack of specific regulation and lack of knowledge of which existing one might be applicable, but even when legal action is taken, noise is hard to evaluate mainly because noise sources are off when authority shows up.
Call synchronization in Neoconocephalus nebrascensis (Orthoptera, Tettigoniidae): Cooperation rather than competition?
Authors: Schul Johannes , Klymus Katy E. , Deily Joshua A.
Published: October 2013

Male calls of the katydid Neoconocephalus nebrascensis consist of 1000-ms-long verses separated by silent pauses of 800 ms. Verses of neighboring males exhibit remarkable synchrony during which leader-follower relationships often remain unchanged over extended periods of time. Such call synchrony is often the consequence of female preference for leading calls. We tested female phonotaxis on a walking compensator in response to male calls presented alone or as pairs. Females did not respond to continuous calls, but required a distinct verse structure for positive phonotaxis. Surprisingly, more than 18-dB modulation depth between verses and silent pauses was required to elicit female responses. When the delay between two simultaneously presented calls was between 0 and 600 ms, females did not exhibit any biologically relevant leader preference. Females did not show significant phonotaxis to alternating calls. Given that females require a modulation depth of 18 dB, call alternation even between distant males would effectively mask the attractive temporal pattern of both males’ calls. Only through call synchronization do males achieve an attractive pattern. This, together with the absence of a biologically relevant female preference for leading calls, indicates that males do not compete but rather cooperate during call synchronization to preserve an attractive temporal call pattern.
Chorusing in fishes
Authors: Mann David , Locascio James
Published: October 2013

Many fishes in the family Sciaenidae engage in nightly chorusing events where sound production starts near dusk and lasts for several hours. This paper examines the periodicity and dynamics of chorusing in the Sciaenidae. Underwater acoustic recorders have been deployed in southwest Florida to record sound production with a high temporal resolution (10 s of recording every 10 min) over a large spatial area. Sound production was dominated by three sciaenid species: silver perch (Bairdiella chyrsoura), sand seatrout (Cynoscion arenarius), and spotted seatrout (Cynoscion nebulosus). Sounds produced by black drum (Pogonias cromis), gafftopsail catfish (Bagre marinus), and gulf toadfish (Opsanus beta) were also recorded. Sound levels in sciaenid choruses typically reach levels of approximately 110–120 dB re 1 μPa spectrum level, and are among the loudest sources of sustained ambient noise in temperate and subtropical coastal waters. Little is known about the behavior accompanying sound production, because it occurs in turbid water at night. The use of hydrophone arrays to document fine-scale spatial patterns of sound production will be discussed.
Social complexity can drive vocal complexity: Group size and information in chickadee calls in Carolina chickadees
Authors: Freeberg Todd
Published: October 2013

There is considerable variation in systems of vocal communication in animals. One hypothesis to explain this variation is that the complexity of the social group influences the groups vocal complexity. This social complexity hypothesis for communication is also central to recent arguments for human language origins, but experimental tests of the hypothesis are lacking. This study investigated whether group size, a fundamental component of social complexity, influenced the complexity of the chickadee call, a call system functioning in social organization of Carolina chickadees, Poecile carolinensis. This call system has been studied in chickadees and related species, and is structurally and functionally rich in its note composition. Complexity of calls was measured using uncertainty (diversity) related to note composition, based on Shannon’s mathematical theory of communication. In unmanipulated field settings, calls of individuals in larger groups had greater complexity (more information) than calls of individuals in smaller groups. In aviary settings manipulating group size, individuals in larger groups used calls with greater complexity than individuals in smaller groups. These results indicate that social complexity can influence communicative complexity in this species.
Vocal exchanges in wild bottlenose dolphins
Authors: Quick Nicola J. , Janik Vincent M.
Published: October 2013

This study investigated the behavioral context of stereotypic whistle exchanges in wild bottlenose dolphins off north-east Scotland to infer function from whistle usage. Concurrent acoustic and nonacoustic behavioral data sampling was conducted during focal follows. Passive acoustic localization using a four-element distributed array was used to identify vocal exchanges (i.e., whistles from different individuals within 3 s of each other). Vocal exchanges of stereotypic (two whistle types produced repeatedly by at least two animals) nature occurred during 12 focal follows from 10 separate days containing 108 whistles that could be localized. Exact randomization tests (10 000 iterations), using whistles from exchange and nonexchange periods within each follow, showed that the observed number of exchanges (i.e., whistles produced by different individuals within 5 s of each other) was significantly different than the value that resulted from randomization. Vocal exchanges occurred prior to dolphin subgroups joining in 9 out of 10 observed joins. Only 2 of 11 vocal exchanges were not followed by a join. Vocal exchanges of stereotyped whistles between individuals appear to be important in coordinating joins in wild dolphin groups. Further analysis of exchange whistles showed that their degree of stereotypy equalled that found in signature whistles.
Convergence of calls as animals form social bonds
Authors: Tyack Peter L.
Published: October 2013

In many species capable of vocal production learning, the acoustic properties of calls from different individuals can converge when they are housed together in captivity or form social bonds in the wild. This has been demonstrated for animals as diverse as songbirds, parakeets, bats, cetaceans, and primates. In many species of songbirds, territorial neighbors have repertoires with several shared songs. Males can use the shared songs during territorial disputes, and birds escalate or de-escalate a countersigning interaction by choosing to reply with a song match, a repertoire match, or an unshared song. For most other species, call convergence is thought to reflect a group-distinctive identifier, with shared calls reflecting and strengthening social bonds. I will discuss examples of call convergence in primates, birds, elephants, and cetaceans. The breadth of the use of production learning for call convergence suggests that this may have been an important selective pressure for the evolution of production learning. Some species have well-developed capabilities of imitating distinctive calls of other individuals or groups. This capability of learning to imitate an arbitrary signal for an arbitrary referent may have evolved out of simpler forms of vocal convergence.
Localization and geoacoustic inversion by using 20-Hz signals of finback whales on the New Jersey Shelf
Authors: Turgut Altan , Pasewark Bruce
Published: October 2013

One-second duration 20-Hz signals of finback whales were recorded on three vertical line arrays (VLAs) and a bottomed horizontal line array (HLA) during the RAGS03 experiment conducted on the New Jersey Shelf. Modal analysis indicated that most signals, recorded over a 3-week period in December of 2003, contained a weak, early-arriving mode-2 and strong, late-arriving mode-1 component. These modal characteristics are exploited in a broadband matched-field algorithm to localize individual finback whales and to perform geoacoustic inversions. Bearing estimation of individual whales is obtained by performing horizontal beamforming on the HLA data. Range estimation results are verified by time-of-flight triangulation using single hydrophone data from each VLA location. Geoacoustic inversion results were comparable to those previously obtained from chirp sonar data. Localization results indicated that most finback whales traveled near the shelfbreak front where food might be abundant. [This work was supported by the ONR.]
A method to reduce geoacoustic inversion uncertainties caused by water column fluctuations
Authors: Lin Ying-Tsong , Lynch James F.
Published: October 2013

A linear method is developed to reduce the effects of small sound-speed fluctuations in the water column on geoacoustic inversions. Sound-speed fluctuations are considered as a source of physical model error, and their influence on the acoustic data used for determining geoacoustic parameters is estimated by linear perturbation theory. The idea of this method is to project acoustic data onto a space that is insensitive to water sound-speed fluctuations. To determine this space, the singular value decomposition is applied to the kernel of the linear perturbation equation, which links the fluctuations to the acoustic data. This approach will reduce the number of data points available for inversion. Because of this, empirical orthonormal function analysis is employed to represent the sound-speed fluctuations by a small number of modes, which effectively increases the number of projected data points. This method is demonstrated by a numerical test case, using linear internal waves with the Garrett-Munk spectrum to vary the water column in time and space. The influence of the higher-order terms neglected in the linear perturbation equation on the performance of this method is also discussed.
Validation of statistical estimation of transmission loss in the presence of geoacoustic inversion uncertainty
Authors: Huang Chen-Fen , Gerstoft Peter , Hodgkiss William S.
Published: October 2013

Often the ocean acoustic environment is not well known and sonar performance prediction will be affected by this uncertainty. Here, a method for characterizing transmission loss (TL) is proposed which incorporates these environmental uncertainties. The statistical estimation of TL based on the posterior probability density of environmental parameters obtained from the geoacoustic inversion process is the main theme of this study. First, a Markov chain Monte Carlo procedure is employed to sample the posterior probability density of the geoacoustic parameters. Then, these parameter uncertainties are mapped to the transmission loss domain, where a full multidimensional probability distribution of TL as a function of range and depth is obtained. In addition, TL is also characterized by its summary statistics including the median, percentiles, and correlation coefficients. The approach is illustrated using a data set obtained from the ASIAEX 2001 East China Sea experiment. Based on the geoacoustic inversion results, the predicted TL and its variability are estimated and then compared with the measured TL. In general, the results show that approximately 80% of the observed TL data fall within 90% of the TL probability distribution.
Passive matched-field inversion for thick-sediment characterization
Authors: DelBalzo Donald R. , Linzell Robert S. , Pflug Lisa A.
Published: October 2013

Acoustic field estimation in shallow-water, littoral areas is severely limited by environmental uncertainty, especially regarding sediment property characteristics. Direct methods of obtaining geophysical data are expensive, so inverse methods have recently become popular. Most techniques rely on inverting signals from controlled active sources. This work is focused on inverting signals with unknown source levels from surface ships of opportunity at unknown ranges. A range-staggered technique is employed to create a range-dependent sediment description, with ever-increasing confidence as additional surface ships are analyzed. Matched-phase techniques are applied in a simulated shallow-water environment with a single vertical array and high signal-to-noise ratios. The inversion process is evaluated as a function of frequency bandwidth, number of hydrophones, and array length. The simulations indicate significant potential for passive, range-dependent, thick-sediment characterizations out to ranges of tens of water depths in shallow water. [Work sponsored by SPAWAR.]
Sediment models for the East Coast based on a priori information, geological data, and sediment inversions
Authors: Potty Gopu R. , Miller James H. , Lynch James F.
Published: October 2013

A preliminary sediment model for the U.S. East Coast with particular emphasis on the Shallow Water-2006 experimental site is presented. This sediment model will describe the bottom as layers of sediments with different properties. The layering information will be based on geological, geophysical, stratigraphy models and inversion results. The surface sediment description will be based on the Effect of Sound on Marine Environment (ESME) sediment models for the U.S. East Coast. This sediment model, developed as part of the ESME initiative, draws from a variety of data sources including the sediment texture database maintained by the United States Geological Survey. This database coupled with Hamilton, Biot-Stoll (with reduced number of parameters), or Buckingham models (to define the sediment geoacoustic properties) has the potential for providing an efficient surface sediment representation with large spatial coverage. Other sources of data, which will be used to develop the preliminary sediment model, include published sediment core data from the region and inversions results. The use of empirical orthogonal function-based sediment parametrization for inversions will be explored. This study will provide sediment data for the preliminary experimental design efforts prior to the experiment in 2006. [Work supported by Office of Naval Research.]