bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-dimensional space representation by echolocation in bats
Authors: Wohlgemuth Melville J. , Kothari Ninad B. , Moss Cynthia F.
Published: October 2015

Echolocating bats are equipped with a biological sonar system that permits spatial navigation and target tracking in complete darkness. By actively controlling the directional aim, timing, frequency content, and duration of echolocation signals to “illuminate” the environment, the bat directly influences the acoustic input available to its sonar imaging system. Detailed analyses of the bat’s sonar behavior suggest that the animal’s actions play into a rich 3-D representation of the environment, which then guides motor commands for subsequent call production, head aim, and flight control in an adaptive feedback system. Studies of the bat’s sonar behavior have motivated neurophysiological studies of the midbrain superior colliculus (SC), a structure implicated in sensorimotor integration and spatial orientation. Using multichannel silicon probe recordings from the freely echolocating big brown bat, we characterized response profiles of single neurons, as the animal tracked moving targets from a stationary position on a platform and in free flight. Our data show premotor activity prior to sonar vocalizations and responses to echoes from objects. Echo responses depended on both the azimuth and delay of sonar returns. These findings demonstrate both auditory and premotor specializations in the bat SC, which contribute to the animal’s 3-D representation of space.
Neural processing of novel sounds in the rat’s inferior colliculus
Authors: Zhang Huiming , Patel Chirag , Lumani Ariana
Published: October 2015

A novel sound is an occasionally occurring acoustic event in a constant/repetitive acoustic environment. Auditory neurons display sensitivity to a novel sound by reducing action potential discharges over repetitive acoustic stimulation and restoring discharges upon presence of a novel sound. We used the rat as an animal model and conducted in vivo neurophysiological recordings to examine how novel sounds are processed in the midbrain auditory structure, the inferior colliculus (IC). The IC receives convergent inputs from structures including those with neurons sensitive to novel sounds. These inputs have diverse sensitivities to temporal, spectral, and directional acoustic cues and produce excitatory/inhibitory synaptic events with different time courses in IC neurons. Integration among these inputs in IC neurons provides a likely physiological basis for processing the novelty of a sound and other dynamic acoustic characteristics. We used both closed- and free-field stimuli to examine responses to oddball paradigms. Our results indicate that neurons sensitive to novel sounds existed in the IC. These neurons typically have onset firing patterns; and their sensitivity to a novel sound is affected by the spatial relationship between the novel sound and a repetitive standard sound in the environment. [Research supported by NSERC of Canada.]
Sound-triggered suppression of neuronal firing in the auditory cortex: Implications to the residual inhibition of tinnitus
Authors: Galazyuk Alexander
Published: October 2015

Tinnitus can be suppressed briefly following the offset of an external sound. This phenomenon, termed “residual inhibition,” has been known for almost four decades, although its underlying cellular mechanism remains unknown. In our previous work, we have shown that the majority of neurons in the inferior colliculus (IC) exhibit long lasting suppression of spontaneous activity following the offset of an external sound. The time course of suppression corresponded to the time course of residual inhibition in tinnitus patients. If the suppression is an underlying mechanism, the auditory cortex (AC) neurons should also exhibit suppression because residual inhibition of tinnitus is a perceptual phenomenon. To test this hypothesis, we studied sound evoked suppression in AC neurons of awake CBA/CaJ mice using extracellular recording. Pure tones at neurons’ characteristic frequency and/or wideband noise stimuli 30 s duration were delivered in the free-field. We found that AC neurons exhibited sound-triggered suppression of their spontaneous firing. Similar to the IC, the duration of this suppression was roughly corresponded to the stimulus duration (about 30 s). AC neurons also showed longer suppression to tones at their characteristic frequency than to wideband noise. Our data suggest that suppression may be a neural correlate of the residual inhibition of tinnitus in humans. [Work supported by Grant R01 DC011330 from the National Institute on Deafness and Other Communication Disorders.]
A seven-year review of ambient acoustic environments in the Beaufort Sea
Authors: Seger Kerri D. , Thode Aaron M. , Blackwell Susanna B. , Kim Katherine H.
Published: October 2015

Over seven seasons (2007 to 2014) Greeneridge Sciences, Inc., deployed passive acoustic recorders (DASARs) between August and October at five sites in the Beaufort Sea off the Alaskan North Slope to collect acoustic data during the fall bowhead whale migration. Each site consisted of 7–11 DASARs, arranged in triangular grids with 7 km spacing between each unit. The shallowest DASAR unit in each set was deployed 15–33 km due north of the coast in 22–39 m of water. The acoustic environments between sites differ due to varying ocean depths and sound source contributions (whales, winds, and human activities). Here, we conduct a multi-year bulk analysis of the summer Beaufort Sea acoustic environment, comparing noise properties as a function of both distance offshore and longitude within a given year, and across sites across all eight seasons. Comparisons were conducted by investigating the percentile distributions of ambient noise intensity over several bandwidths that are representative of the different sound sources present in the Beaufort Sea. Results suggest that variations in the ambient noise field across sites and years create spatially heterogeneous acoustic environments that must be accounted for when addressing responses of bowhead whales to industrial noise.
Modal analysis of broadband signal arrival on Beaufort shelf
Authors: Badiey Mohsen , Wan Lin , Muenchow Andreas , Knobles David
Published: October 2015

Using previously reported temperature and salinity data collected over the past decade, time evolving sound speed profiles were constructed and used (Prog. Oceanography, 127, pp.1-20, 2014) as input to a parabolic equation model. Modeling of broadband acoustic signal propagation in the Arctic shelf-basin region during ice free sea surface season was reported recently (J. Acoust. Soc. Am. 136(4), Pt. 2, 2317, 2014). It was shown that when broadband acoustic signals propagate from deep water to shallow water, the modal dispersion is changed. The change is mostly affected by the water thermocline behavior in time and space and by source depth. The modal arrival structure can be influenced by a number of factors including the degree of Pacific warm water intrusion, upwelling of the warm saline Atlantic water into the cold surface layer, the range-dependence of the water layers over the shelf break, and the depth of the source. In this paper, we analyze the range-dependent propagation in terms of adiabatic and coupled mode regimes in order to explain the model results. [Work supported by ONR.]
Investigating the effects of ocean layering and sea ice cover on acoustic propagation in the Beaufort Sea
Authors: Sagers Jason D. , Ballard Megan S. , Knobles David P. , Badiey Mohsen , Muenchow Andreas
Published: October 2015

Over the past several decades, the Beaufort Gyre has experienced changes in sea-ice freshwater accumulation and ocean stratification which has implications for long-range acoustic propagation. In this talk, acoustic propagation from the Canadian Basin to the Alaskan Beaufort Shelf is modeled using measurements of physical oceanography and sea ice. Water masses that impact acoustic propagation and stratification in the basin include the warm, saline Atlantic Water (AW), which is overlain by cooler, less-saline Pacific Winter Water (PWW). Oceanographic observations reveal intrusions of a warmer, fresher water mass called Pacific Summer Water (PSW). This water mass resides below the surface mixed layer, but above the PWW and reduces acoustic interaction with the sea-ice canopy for source depths located in the halocline duct. Oceanographic data indicate that on the continental shelf, the PSW intrusion can be absent in the ice-covered months resulting in an upward refracting sound speed profile. Using measurements from ice-tethered profilers in the basin and oceanographic moorings on the shelf, we model the temporal and spatial variability of the acoustic field. The effect of scattering from the ice cover is included, with consideration given to the seasonal variability of sea-ice concentration, thickness, and acoustic properties. [Work supported by ONR.]
Observations of thermohaline sound speed structure in the Beaufort Sea in the summer of 2015
Authors: DiMaggio Dominic , Pearson Annalise , Colosi John A.
Published: October 2015

Moored observations of temperature and salinity were made in the depth of range 50–510 m between July 15 and August 15 2015 in the central Beaufort Sea, as part of the Canada Basin Acoustic Propagation Experiment (CANAPE) pilot study. This talk will present an analysis of the observed sound speed structure in terms of the fresh upper layer, the Pacific layers, and the Atlantic layer. The talk will also address the space/time scales of fluctuations associated with internal waves, eddies, and diffusive layering (stair cases).
Resolution, identification, and stability of broadband acoustic arrivals in Fram Strait
Authors: Dzieciuch Matthew A. , Worcester Peter F. , Sagen Hanne , Sandven Stein , Geyer Florian , Babiker Mohamed , Beszczynska-Möller Agnieszka , Dushaw Brian D.
Published: October 2015

Fram Strait is the only deep-water connection between the Arctic and the world oceans. An acoustic system for tomography, glider navigation, and passive listening was installed in the central, deep-water part of the Strait during 2010–2012, with the primary objective of improving the estimates of transport through the Strait. Previous tomographic measurements have relied on the travel times of resolved, identified, and stable acoustic arrivals. The oceanographic conditions and highly variable sea ice in Fram Strait provide an acoustic environment that differs substantially from those in other tomographic experiments, however, and results in complex arrival patterns. Comparisons of the measured arrival patterns with predictions based on hydrographic sections show that it is difficult to resolve and identify individual arrivals in the early part of the arrival patterns. In addition, the early arrivals are unstable, with the arrival structure changing significantly over time. Later arrivals that are surface-reflected, bottom-reflected tend to be easier to resolve and identify, as well as more stable. The implication is that inverse methods need to use fluctuations in the overall structure of the early arrivals, which tend to sample the ocean similarly, in combination with the travel times of the later arrivals.
Ambient noise in the Arctic Ocean measured with a drifting vertical line array
Authors: Worcester Peter F. , Dzieciuch Matthew A. , Colosi John A.
Published: October 2015

In mid-April 2013, a Distributed Vertical Line Array (DVLA) with 22 hydrophone modules over a 600-m aperture immediately below the subsurface float was moored near the North Pole. The mooring parted just above the anchor shortly after deployment and subsequently drifted slowly south toward Fram Strait until it was recovered in mid-September 2013. The DVLA recorded low-frequency ambient noise (1953.125 samples per second) for 108 minutes six days per week. Previously reported noise levels in the Arctic are highly variable, with periods of low noise when the wind is low and the ice is stable and periods of high noise associated with pressure ridging. The median noise level at 98 m depth during the first two weeks of May not far from the North Pole had a maximum between 10 and 20 Hz of approximately 75 dB re 1 μPa2/Hz. The background noise levels are at times extraordinarily low, with the 10th percentile over a 108-minute period limited by the self-noise of the hydrophones above approximately 100 Hz (35 and 26 dB re 1 μPa2/Hz at 100 and 1000 Hz, respectively). During this time, the median ambient noise levels increased with depth by roughly 3 dB between 100 and 600 m.
High-frequency ultrasound of histology mimicking phantoms for evaluating breast cancer surgical margins
Authors: Cowan Nicole , Coffman Zachary A. , Omer Robyn K. , Doyle Timothy E.
Published: October 2015

The ability to differentiate between malignant and normal tissues in surgical margins during breast cancer surgery would reduce the risk of local recurrence and subsequent surgeries. Clinical studies at the Huntsman Cancer Institute show that high-frequency (HF) ultrasound (20–80 MHz), and the parameters peak density (number of spectral peaks and valleys in the 20–80 MHz range) and attenuation, are sensitive to breast tissue pathology. The objective of this study was to determine the effect of tissue microstructure on these parameters using histology mimicking phantoms. Phantoms were created from distilled water, agarose powder, 10X TBE stock solution, and polyethylene microspheres to simulate breast tissue histology. Microsphere size (59–925μm diameter) and weight percent (0.00–0.06g) were varied in the experiments. Pitch-catch measurements were acquired using 50-MHz transducers, a HF pulser-receiver, a 1-GHz digital oscilloscope, and glycerol as the coupling agent. Both peak density and attenuation showed sensitivity to microsphere diameter and the number of scatterers present. Peak density followed an inverse-size relationship to microsphere diameter, whereas attenuation showed a sensitivity to the total weight percent of scatterers. The phantom results confirm that peak density and attenuation are complementary parameters for characterizing breast tissue pathology and validate the clinical studies.
Measuring the cytoskeletal properties of cell cultures using high-frequency ultrasound
Authors: Behan Ashley , Carter Caitlin , LaFond Amy A. , Sanjinez Dolly A. , Marvel Mandy H. , Doyle Timothy E.
Published: October 2015

High-frequency ultrasound (10–100 MHz) has been demonstrated to be sensitive to cell cytoskeletal changes. Cytoskeletal properties determine the biomechanical characteristics of cells and their role in many biomolecular processes. Examples include the aggressiveness and metastatic potential of breast cancer subtypes, T-cell activation during immune responses, and microtubule disintegration in Alzheimer’s disease. The objectives of this work were to optimize the use of high-frequency ultrasound to subtype breast cancer cells and to acoustically measure cytoskeletal modifications. Pulse-echo measurements of 7 breast cancer cell lines of different molecular subtypes were acquired over a 2.5-year period using a 50-MHz transducer immersed in the growth media of monolayer cell cultures. Cell reflections were isolated from the interfering cell-culture plate reflections, spectrally analyzed using Gaussian curve fits, and spectrally classified using a heat map. The heat map displayed distinct patterns that differentiated the cell lines by molecular subtype. Cell cultures were also treated with colchicine and sphingosylphosphorylcholine to observe modulation of the microtubule and actin components. Cell waveforms and spectra displayed time-dependent changes due to chemical modification of the cytoskeleton. These results further verify and improve the noninvasive use of high-frequency ultrasound to differentiate breast cancer subtypes and to monitor cytoskeletal alterations in real time.
High-frequency ultrasound (20–80 MHz) for analyzing breast cancer surgical margins: A 73-patient clinical study
Authors: LaFond Amy A. , Carter Caitlin , Omer Robyn K. , Factor Rachel E. , Neumayer Leigh A. , Doyle Timothy E.
Published: October 2015

Results from a 2010 pilot study indicate that the peak densities of high-frequency (HF) ultrasonic spectra (20–80 MHz) correlate to a wide range of margin pathologies from breast conservation surgery (BCS). Utah Valley University and the Huntsman Cancer Institute conducted a follow-up study to determine the sensitivity and specificity of HF ultrasound for differentiating malignant from nonmalignant tissue in BCS margins. A 73-patient blind study was performed with conventional pathology used as the gold standard. A total of 492 specimens were ultrasonically tested ex vivo and then sent to pathology for analysis. The margins were approximately 3x20x20 mm, with each sampled at 2–5 locations. The data were analyzed for malignancy using peak density. Results from the current study indicate that peak density can differentiate malignant from nonmalignant pathologies with an accuracy of 73.8%. Trends from the pilot study closely resemble this study’s results. Application of these trends to the current study predicts that a multivariate analysis will yield much higher accuracy (84.1%), specificity (85.2%), and sensitivity (77.6%) values. The results show that HF ultrasound can provide rapid, intraoperative evaluation of surgical margins, thereby increasing the quality and efficacy of breast cancer surgery. [Funding provided by the Elsa U. Pardee Foundation.]
High-frequency ultrasound for evaluating margins during breast conservation surgery: Results from a 17-patient pilot study
Authors: Omer Robyn K. , Sorensen Kristina M. , Neumayer Leigh A. , Factor Rachel E. , Doyle Timothy E.
Published: October 2015

Obtaining negative (cancer-free) margins in breast conservation surgery (BCS) is essential for ensuring all of the cancer has been removed from the excision site. Several rapid, noninvasive cancer detection methods are therefore being investigated for the intraoperative evaluation of margin status. This study investigated high-frequency (HF) ultrasound (20–80 MHz) as an intraoperative margin evaluation technique during BCS. In a 17-patient pilot study at the Huntsman Cancer Institute, Salt Lake City, Utah, through-transmission and pulse-echo measurements were acquired from 53 positions on specimens including margins, tumors, lymph nodes, and fibroadenomas. Measurements were acquired with the use of two 50-MHz transducers, a HF square-wave pulser/receiver, a 500-MHz digital oscilloscope, and a notebook PC. Parameters calculated from the data included peak density (the number of peaks and valleys across the ultrasonic spectrum), attenuation, and the slope of the second Fourier transform. Statistical analysis of the data revealed that a multivariate analysis combining peak density and attenuation provided the highest accuracy and sensitivity for differentiating malignant from nonmalignant tissue. The multivariate analysis showed 81.1% accuracy, 76.9% sensitivity, and 85.2% specificity. The results demonstrate that HF ultrasound is competitive with 2D specimen mammography and radio-frequency spectroscopy for margin evaluations. [Funding provided by Utah Valley University.]
A compensation method of frequency-dependent attenuation for pulsed Doppler systems by adapting the transmitting waveform
Authors: Nishimura Jun , Teshima Yu , Hiryu Shizuko , Akiyama Iwaki
Published: October 2015

Pulsed Doppler systems require a high signal-to-noise ratio (SNR) to differentiate the low amplitude of the blood flow echoes from the floor noise. Conventional quadrature demodulation (QDM) assumes that the central frequency of the emitted pulse is the same as the received echoes and uses this frequency as demodulation frequency. Nevertheless, the central frequency of the received echoes is actually downshifted due to the frequency-dependent attenuation (FRDA). This downshifting produces loss of SNR due to discarding energy of the down-mixed signal. In this study, by estimating the spectrum of a Gaussian modulated pulse, the downshift caused by the FRDA was obtained to create a new compensated pulse with the aim of forcing the echo central frequency to match with the demodulation frequency. The method was evaluated by using Field II simulation. Considering an attenuation of 0.5 dB/MHz/cm, a 5 MHz transducer and a relative bandwidth of approximately 50%, at a depth of 16 cm, compensated pulses reduced the frequency shift from 1.11 to 0.32 MHz and the SNR degradation from 9.25 to 0.41 dB. [This study was supported by the MEXT-Support Program for the Strategic Research Foundation at Private Universities, 2013–2017].
The effect of ambient pressure on the color Doppler ultrasound twinkling artifact
Authors: Simon Julianna C. , Cunitz Bryan W. , Sapozhnikov Oleg A. , Kreider Wayne , Thiel Jeffrey , Holm James R. , Sorensen Mathew D. , Bailey Michael R.
Published: October 2015

Recently, our group discovered that overpressure suppressed the color Doppler ultrasound twinkling artifact on ex vivo calcium oxalate monohydrate (COM) kidney stones, suggesting that trapped microbubbles on the stone surface cause twinkling (Lu et al. 2013). Yet the hypothesis is not fully accepted, partly because bubbles were not observed. Here, we extend the overpressure results to include under-pressure and use high-speed photography to visualize the bubbles. A programmable ultrasound system with Philips/ATL P4-2 transducer was used. Ex vivo COM stones were placed in a hydraulic pressure chamber and imaged acoustically through an acrylic window. The overpressure threshold to diminish twinkling was found to vary significantly, with twinkling eliminated at pressures of 3 ATA (atmospheres absolute) up to >8 ATA, even within the same stone. When the stones were exposed to 0.2 ATA (under-pressure), twinkling increased. High-speed photography during Doppler ultrasound revealed only one instance of an oscillating bubble. However, when stones were exposed repeatedly to a pre-focal, off-axis lithotripter pulse (p+ = 1.5 MPa, p- = 2.5 MPa), stones that twinkled had bubbles emerge from the same location with each pulse whereas stones that did not twinkle had a random bubble distribution. [Work supported by NSBRI through NASA NCC 9-58 and NIH DK043881, DK092197.]
Development of complex tissue-mimicking phantoms for quantification of flow by the time-intensity method in contrast enhanced ultrasound imaging
Authors: Pawar Asawari , Clement Gregory , Howell Mark
Published: October 2015

Currently, there are few simple-to-construct in vitro, wall-less phantoms that have accurate acoustic properties while mimicking the complex normal and neoplastic geometries of the vascular network. The purpose of this study was to develop agar-based tissue-mimicking phantoms (TMP) to model such networks. Three types of vascular networks were considered: (1) single vessel, (2) multi-vessel with artery bifurcations, and (3) multi-vessel with artery bifurcations and structural abnormalities typical of diseased (tumor) vascular networks. Blood-flow related parameters were derived from the time-intensity curves obtained from the bolus injection of a lipid-based microbubble ultrasound contrast agent (UCA) under varying flow conditions relevant to our ongoing work in developing techniques to simultaneously quantify both the total volume and flow measurements within a tumor phantom. A Fukuda Denshi Ultrasound system was used with a linear probe (LG308-16A) positioned transversely and longitudinally to the direction of the flow. B-mode image acquisition was performed with 0.5 mL of UCA bolus injected into a 500 mL degassed water reservoir and then pumped through the vessels at rates ranging from 20 mL/min to 100 mL/min. Offline analysis of time-intensity curves in response to varied flow conditions indicated the TMP ability to yield easily reproducible simulations of vascular microcirculation.
Kidney stone specific ultrasound imaging of human subjects
Authors: Cunitz Bryan W. , Dunmire Barbrina L. , Bailey Michael , Haider Yasser , Maxwell Adam D. , Simon Julianna C. , Thiel Jeff , Sapozhnikov Oleg A. , Harper Jonathan D. , Sorensen Mathew D.
Published: October 2015

Sensitivity and specificity data show users have more difficulty in identifying stones accurately in B-mode ultrasound than x-ray CT. Our goal was to evaluate the signal to noise (SNR) of a new stone specific imaging algorithm, S-mode based on Color Doppler twinkling artifact, to B-mode. Forty sets of B- and S-mode imaging data were collected from 16 subjects using a Philips HDI C5-2 imaging probe and Verasonics ultrasound system. Two ways S-mode differs from Doppler is that it filters out blood flow signal and uses reverse color write priority to add color to echogenic regions only. For both B- and S-mode raw data, we calculate SNR of the magnitude (brightness) of the stone signal compared to the second highest magnitude in the image. The mean and standard deviation of the SNR was 1.6 ± 0.7 for B-mode and 37 ± 24 for S-mode, with 1 being the stone is equally bright as, and difficult to distinguish from, background. In this human study of S-mode, stones appeared over 30 times brighter than background and with over 20 times the contrast to background seen in B-mode. [Work supported by NIH NIDDK grants DK043881 and DK092197, and NSBRI through NASA NCC 9-58.]
Virtual acoustic environments for soundscape research and urban planning
Authors: Vorlaender Michael , Stienen Jonas
Published: October 2015

The utilization of Virtual Reality technology offers fascinating perspectives for the assessment of urban environments regarding the comfort, well-being, feeling of safety, and public health. Such technology, if available with a user-friendly software interfaces to existing and future planning tools, will expand the planning process into an integrative approach. Apart from sound, this may also involve vision and other aspects such as air pollution or climate change. The future design outline of the buildings, city quarters, and cities up to megacities can be assessed by taking the different perceptual modalities into account in an integrative procedure. Facilitating Virtual Reality for future environments in the assessment of new urban projects enables the population to get involved and renders the procedure more ecologically valid. Thus, by inclusion of the population, large counterforces, even demonstrations, or citizen’s initiatives against urban or transport development (e.g., current discussions about infrastructure, airports, railway line planning, and wind farms) could be avoided. Recent developments in Virtual Reality technology for the built environment are highlighted by focusing on acoustics and noise control but also integrating vision, climate change, and other aspects of the multimodal indoor and outdoor assessment of comfort.
Acoustical impact of wind turbines on soundscape
Authors: Genuit Klaus , Fiebig Andre , Schulte-Fortkamp Brigitte
Published: October 2015

It is well known that wind turbines have a negative impact on the landscape. But what is their impact on soundscape? Is this independent from the visual perception? Increasing research efforts are made to explain annoyance and complaints caused by wind turbines in detail, but still several questions are unanswered. The acoustical contribution of wind turbines depends on the technical design of the generator and of the blades. All of them produce low frequencies; some of them produce noise in the middle and higher frequencies with tones and modulations. It is clear that the A-weighted sound pressure level is not the appropriate indicator to predict resulting annoyance. The question is what must be considered to understand the perceived sound quality within the context of soundscape? Are psycho-acoustical parameters able to describe the sound character of wind turbines in a better way? To get an improved understanding of the complex interactions of the sound produced by wind turbines and the existing sounds of a given soundscape basic studies were performed and the results will be presented.
Soundscape of a wind farm—The Cape Bridgewater experience
Authors: Cooper Steven E.
Published: October 2015

The general concept for describing the noise environment in proximity to a wind farm is expressed in terms of the A-weighted level that will vary dependent upon the wind strength. The compliance methodology in general use for wind farms relies upon a measurement that includes wind and an average line of fit through such data. Measurements at residential receivers when conducted using full spectrum recording/analysis revealed unique characteristics extending into the infrasound region that are normally inaudible that would appear to be present when disturbance is noted. There are no traditional dose-response investigations for the full spectrum of wind farm noise on which to describe the soundscape. A new approach to assessing wind farm noise emissions was used for the Cape Bridgewater wind farm study identifying different concepts for describing the soundscape of the wind farm
Uses of soundwalks in computer modeling of soundscapes during the design process
Authors: Siebein Gary W. , Roa Marylin , Siebein Gary W. , Paek Hyun G. , Jones Paul C.
Published: October 2015

This paper presents a case study of the use of soundwalks to gather data for computer simulations of complex soundscapes while they are being designed. A soundwalk is a process where people enter an existing soundscape for listening, observation, measurement, recording or evaluation. This project is for a new mixed use urban center. Studies were undertaken to investigate the soundscape of this new community both within the community itself as well as outside the community while it was being designed. Soundwalks were taken through existing communities with similar buildings, urban spaces and infrastructure to those being proposed in the design. Acoustical measurements made during the soundwalks of specific acoustic events that occurred in the communities were used as input data for sound sources in a large, three dimensional computer model of the site and its environs. The model was used to estimate future sound levels from the mix of activities in the new community. Aural recordings of the specific acoustic events were used in aural simulations of the spaces where stakeholders could evaluate the acoustical conditions in the community and provide insights into the design of the soundscape.
Comparison of urban and rural soundscapes associated with Dumetella carolinensis and Cardinalis cardinals
Authors: Knobles David P. , Badiey Mohsen , Wilson Preston S.
Published: October 2015

Both the acoustic transmission properties of the environment and the ambient noise field are factors that affect avian soundscapes. Long-term acoustic measurements made with Song Meter SM2 + recorders in both Texas and Delaware are analyzed for the information they contain on soundscapes as they pertain to songbirds, such as Dumetella carolinensis, commonly found in Delaware, and Cardinalis cardinals, common to both Delaware and Texas. The measurements in both states are made in both urban and rural environments and in coincidence with physical measurements of temperature, humidity, wind speed, and direction. Additional acoustical measurements are made with other sound recorders to gain more specific information about, for example, the dawn chorus. The efficacy of using the characteristics of the chorus as an indicator of the health of the avian soundscape is discussed. Band limited cross-correlation methods are used to test various hypotheses on bird communication and behavior.
Residents’ sound preference of rural soundscape in China
Authors: Ren Xinxin , Kang Jian , Jin Hong
Published: October 2015

The importance of rural soundscape has been recently recognized for the recreational and amenity value, where man-made noise is at a low level and the dominance of natural sounds promotes sound preference, but there is a lack of studies on the sound preference of residents in the villages of China, which are undergoing a fast development in urbanization. In this study, a questionnaire survey was undertaken at 36 villages of northeast regions, representing all major soundscape types. The results show that among the individual factors, age, education level, and landscape environment are more significant than the factor of gender, in terms of influence on sound preference. With increasing age, the sound preference of traffic and mechanical sound has a tendency of increase and then decrease, whereas the tendency for human voice, natural, and melody sound is opposite. With a higher education level, the sound preference of traffic, mechanical sound, and human voice decreases, and on the contrary, sound preference for natural and melody sound increases. However, the evaluation of natural and melody sound is lower in better landscape environment, which is perhaps due to the residents’ higher requirements in soundscapes corresponding to the landscapes.
Propagation of pulsed ultrasonic fields in a band gap of a two dimensional phononic crystal
Authors: Koju Ukesh , Mobley Joel
Published: October 2015

A band gap in the transmission spectrum of a finite two dimensional phononic crystal is examined in the time domain using pulsed ultrasonic fields. The phononic crystal consists of a hexagonal array of copper cylinders (r = 1.19 mm) in an aqueous matrix with a lattice constant of 2.9 mm. Measurements of the transmission properties of the sample are performed using ultrasonic wave groups of various center frequencies and bandwidths. Among the band gaps in the low-MHz range, we concentrate on the gap from 1.48 MHz—1.70 MHz. The phase velocity, group velocity, and attenuation coefficient spectra are determined and compared with expectations.
Acoustic scattering cancelation in an aqueous environment using phononic crystals
Authors: Guild Matthew D. , Martin Theodore , Rohde Charles , Calvo David , Orris Gregory
Published: October 2015

Acoustic scattering cancelation is an approach that enables the elimination of the scattered field from an object within the surrounding medium. While this cancelation effect can be achieved through the use of a single, isotropic fluid, such a simple design limits its application to objects that are small compared to a wavelength. More complicated multilayered fluidic coatings are necessary for the cancellation of higher order scattering modes. Such modes arise from objects with characteristic lengths comparable to the incident wavelength in the surrounding medium. To realize such a coating, phononic crystals offer a means for precisely designing the necessary structures. In this work, analytical and numerical results will be presented for the acoustic scattering cancellation of cylindrical objects in an aqueous environment using multilayered effective fluid coatings constructed of phononic crystals. [Work supported by the Office of Naval Research and the National Research Council.]
Acoustic phase hologram with labyrinthine metamaterials
Authors: Xie Yangbo , Shen Chen , Jing Yun , Cummer Steven
Published: October 2015

Acoustic metamaterials offer large degree of design freedom and precise control over amplitude and phase at subwavelength scales. In the past, we have demonstrated a family of labyrinthine metamaterial unit cells as premium building blocks for phase modulation devices, as well as several 1D wavefront shaping devices based on these unit cells. Here we extend the complex modulations to 2D by demonstrating a computer generated metamaterial-based phase hologram. Through spatially modulating the phase of the wavefront, the hologram projects the incident wave to a designed three-dimensional amplitude pattern. The hologram is designed with a two-step process: first, an iterative holographic reconstruction algorithm is used to obtain the optimal phase pattern of the hologram; second, unit cells with desired phase modulations are designed and fabricated. Ray tracing and full-wave simulations have been performed to verify the design. The measurements of reconstruction in an anechoic chamber will be taken for a hologram designed to operate around 4 kHz. The metamaterial-based hologram creates a three-dimensional acoustic illusion with only passive structures. The designing process can also be extended to devices such as multi-focal lenses and wave-based analog processing/computing interfaces.
Tomographic sonar image formation of difficult objects and of mines on the seabed
Authors: Ferguson Brian G. , Wyber Ron J.
Published: October 2015

Insonifying a sea mine over a complete (360°) set of look directions, while recording the acoustic returns (or echoes) from the object as a function of aspect angle, enables the two dimensional projection data (or measurement) space to be fully populated. An acoustic image is readily reconstructed by applying Fourier transform methods to the projection data. Tomographic sonar images of various (inert) sea mines are presented, where a fixed monostatic sonar insonifies the object as it rotates about its vertical axis through one complete revolution. A difficulty arises if the specular component returned from one part of the object swamps the returns from the rest of the object. The problem is solved by taking spatial derivatives of the Fourier reconstructed image, which then results in a representation that enables the object to be recognized. Another complication presents itself when structural waves, which are excited by the insonification process, contribute to the observed impulse response. Numerous examples of the effect of these structural waves on the formation of the image are presented for various objects and sonar technologies, including parametric sonar. For operational tomography, the object is fixed (a mine resting on the sea floor), which requires the sonar to circumnavigate the mine (at a safe standoff distance) while simultaneously insonifying it and compiling the multiaspect projection data space. Sample tomographic sonar images of a practice sea mine, a Mk 84 bomb, and the sea floor itself, are presented.
Detection results for a class 1 unmanned aerial vehicle measured with a small microphone array
Authors: Goldman Geoffrey H.
Published: October 2015

The Department of Defense is developing low size, weight, power, and cost (SWaP-C) acoustic systems to detect and track small unmanned aerial vehicles (UAV). To support these goals, an analysis of several detection algorithms was performed using acoustic data generated with a class I unmanned aerial vehicle and measured with a small tetrahedral microphone array. The detection algorithms were based upon the peak output power and the coherence factor of several beamforming algorithms. Receiver operation characteristics (ROC) curves were generated using both an energy-based and a Neyman-Pearson-based detection algorithm.
Change in Canada’s national building code—Assessing flanking sound transmission in concrete-masonry constructions
Authors: Zeitler Berndt , King Frances , Mahn Jeffrey , Hoeller Christoph
Published: October 2015

The proposed 2015 edition of the National Building Code of Canada sees a major change in sound insulation requirements. Instead of prescribing requirements for the separating assembly only (in terms of STC values), the Code now sets requirements for the sound insulation performance of the complete system (in terms of Apparent Sound Transmission Class (ASTC) values), including flanking sound transmission. The National Research Council Canada is actively supporting the change in the Code by conducting various projects with industry associations from different construction sectors, in order to provide tools, guidance, and the necessary data for compliance. This presentation focuses on a joint project between the National Research Council Canada and the Canadian Concrete Masonry Producers Association. In the project, the direct and flanking sound transmission in concrete masonry and hybrid building systems were investigated. For masonry walls in combination with concrete floors, the ASTC values were calculated according to ISO 15712-1. For masonry walls in combination with wood joist floors, the ASTC values were measured according to ISO 10848. Furthermore, the effect of linings on concrete masonry walls was investigated. This presentation will provide an overview of each of these issues, including results and recommendations.
Challenges facing fitness center designers in multifamily buildings
Authors: Harvey Scott
Published: October 2015

Amenity spaces in multifamily and mixed use developments have become extremely popular and possibly mandatory to the economic success of the project. Of these amenity spaces fitness centers are extremely common and pose significant design challenges to the noise control engineer. This paper will compare several mitigation techniques used to control fitness center noise from today' prominent sources including treadmills, group exercise, weight machines, free weights, and cross fit weight drops. Mitigation in both wood and concrete structures will be addressed.
Classification of beaked whale and dolphin clicks measured by environmental acoustic recording system buoys in the northern Gulf of Mexico
Authors: Sidorovskaia Natalia A. , Li Kun , Ackleh Azmy , Tang Tingting , Tiemann Christopher O. , Ioup Juliette W. , Ioup George E.
Published: October 2015

The Littoral Acoustic Demonstration Center (LADC) has used its Environmental Acoustic Recording System (EARS) buoys to record sperm and beaked whales and dolphins, with frequencies up to 96 kHz, in the northern Gulf of Mexico in 2007 and 2010. The 2007 experiment was the first to record beaked whales in the Gulf. It has been found that there is considerable overlap in the band of beaked whale signals from 20 to 60 kHz with deep-water dolphin clicks, so traditional energy-band detectors have a high occurrence of false positives. Although acoustic measurements in this frequency range validated by visual observations have been limited, for the Gulf of Mexico species, progress is being made in automatically delineating clicks that belong to beaked whale species observed in the Gulf and those originating from dolphins. Spectrograms of the classified clicks are shown and compared to known spectrograms for beaked whale and dolphin species. Many of the spectrograms show an upsweep in the observed spectrum but others do not. Improved classifiers can provide higher accuracy estimates of the regional abundance trends and effects of environmental changes on both beaked whale and dolphin groups. [Research supported by BP/GOMRI, SPAWAR, ONR, NSF, and Greenpeace.]
An examination of the biosonar problem associated with sperm whales foraging on jumbo squid in the Gulf of California
Authors: Au Whitlow W. , Benoit-Bird Kelly J. , Gilly William F. , Mate Bruce
Published: October 2015

The backscatter properties of jumbo or Humboldt squid (Dosidicus gigas) were examined in-situ by projecting simulated sperm whale (Physter macrocephalus) clicks to tethered squids. The incident signal was a broadband click with a peaked frequency of approximately 17 kHz. Echoes were collect for three different aspect angles; (broadside, anterior, and posterior, and for different body parts for one squid. The beak, eyes, and arms, probably via the sucker rings, played a role in acoustic scattering though their effects were small. An unexpected source of scattering was the cranium of the squid which provided a target strength nearly as high as that of the entire squid though the mechanism remains unclear. The data support the hypothesis that the pen may be an additional important source of squid acoustic scattering. The detection range of these squids for sperm whales were estimated by performing a parametric analysis. Although many of the squid migrate with the mesopelagic layer towards the surface at night, sperm whales have been observed to forage at depth throughout the day and night which would maintain a relative low echo to clutter ratio, increasing their detection range.
Baleen whale localization using a dual-line towed hydrophone array during seismic reflection surveys
Authors: Abadi Shima H. , Tolstoy Maya , Wilcock William S.
Published: October 2015

Three dimensional seismic reflection surveys use multiple towed hydrophone arrays for imaging the structure beneath the seafloor. Since most of the energy from seismic reflection surveys is low frequency, their impact on Baleen whales may be particularly significant. To better mitigate against this potential impact, safety radii are established based on the criteria defined by the National Marine Fisheries Service. Marine mammal observers use visual and acoustic techniques to monitor safety radii during each experiment. However, additional acoustic monitoring, in particular locating marine mammals, could demonstrate the effectiveness of the observations, and improve knowledge of animal responses to seismic experiments. In a previous study (Abadi et al., 2014), data from a single towed seismic array was used to locate Baleen whales during a seismic survey. Here, this method is expanded to a pair of towed arrays and the locations are compared with an alternative method. The experimental data utilized in this presentation are from the seismic experiment conducted by the R/V Marcus G. Langseth near Alaska in summer 2011. Results from both the simulation and experiment are shown and data from the marine mammal observers conducted simultaneously with the experiment are used to verify the analysis. [Sponsored by NSF.]
Imaging of a fractal pattern with time and frequency domain topological derivative
Authors: Gibiat Vincent , Jacob Xavier , Rodriguez Samuel , Sahuguet Perrine
Published: October 2015

While fractal boundaries and their ability to describe irregularity have been intensively studied, only a few studies are available on wave propagation in a medium where a fractal or quasi fractal pattern is embedded. Acoustical propagation in 1D or 2D domains can be modeled using Time Domain Finite Differences or in Frequency domain with Finite element methods. The fractal object is then considered as a subwavelength set of scatterers, and the problem becomes a multiple scattering one leading to acoustic localization. So, as some important part of the energy remains trapped inside the fractal pattern, imaging such a medium becomes difficult and imaging such complex media with classical tools as B-scan or comparable methods is not sufficient. The resolution of the inverse problem of wave propagation can then be achieved with the help of the more efficient imaging methods related with Time Reversal. Using the concept of topological derivative as defined in Time Domain Topological Energy and Fast Topological Imaging Method, respectively, in Time domain and Frequency domain is powerful in that case. Examples in 1D and 2D will be presented including the image obtained for a sliced sponge.
A non-dispersive discontinuous Galerkin method for the simulation of acoustic scattering in complex media
Authors: Bendali Abderrahmane , Barucq Hélène , Diaz Julien , Fares MBarek , Mattesi Vanessa , Tordeux Sébastien
Published: October 2015

In the context of time harmonic acoustic wave propagation, the Discontinuous Galerkin Finite Element Method (DG-FEM) and the Boundary Element Method (BEM) are nowadays classical numerical techniques. On one hand, the DG-FEM is really appropriate to deal with highly heterogeneous media. In comparison with continuous Finite Elements Method (FEM), this method is well adapted to direct solver since its connectivity diagram is significantly smaller than the one of classical FEM. However, it suffers of numerical pollution: the numerical wave does not propagate at the correct velocity. This can be very problematic when this method is used on very large computational domain or at high frequency. On the other hand, the BEM is one of the most efficient method to deal with homogeneous media, especially when accelerated by a multipole method or thanks to the Adaptive Cross Approximation. Moreover, this method is really less affected by numerical pollution. However, BEM is not adapted to heterogeneous media. In this talk, we would like to present a DG-FEM whose shape functions are defined thanks to a BEM. This new numerical discretization method benefits from the advantages of BEM and DG-FEM: low pollution effect, ability to deal with highly heterogeneous media. Numerous simulations will show the efficiency and the accuracy of the method on large domains.