bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of whistle classification results for three overlapping false whale populations in the Hawaiian Islands
Authors: Barkley Yvonne M.
Published: November 2016

The false killer whale (Pseudorca crassidens) is a globally distributed species found in temperate and tropical waters. The Hawaiian Archipelago is home to three genetically distinct populations of P. crassidens with overlapping distributions: two insular populations, one within the main Hawaiian Islands (MHI) and the other within the Northwestern Hawaiian Islands (NWHI), and a broadly distributed pelagic population. The mechanisms that created and maintain the separation between these populations are unknown, but previous studies have shown that acoustic diversity may reflect the genetic differences. For this study, whistles from 14 MHI, 11 NWHI, and 7 pelagic groups were extracted and measured to assess whether differences exist between the vocal repertoires of each population. Whistle measurements were tested for statistical differences and then used in two different classification methods: a random forest algorithm and Kullback-Leibler (KL) divergence calculations. Preliminary results suggest that the MHI and pelagic populations are vocally distinct, with up to 100% correct classification of whistles for some groups. A comparison of the classification results from the random forest and KL divergence studies will be discussed. Understanding the acoustic differences between these populations may open up new acoustic monitoring approaches for a difficult-to-study species.
The effect of aircraft noise on bird song
Authors: de Kort Selvino R. , Wolfenden Andrew
Published: November 2016

In general, it has been found that birds respond to exposure of anthropogenic noise by singing at a higher frequency range. This is presumably the result of an attempt by the birds to reduce the masking effect of the low rumble of urban noise. In sharp contrast, we report that chiffchaffs reduce song frequency at airports where noise levels are intermittent rather than constant, but at a much higher amplitude level. In addition, we show experimentally that airport birds respond more aggressively to playback of airport songs than the control songs, while a nearby control population does not discriminate between airport and control songs. Potential explanations for these results will be discussed.
Recent progress in Taiwan on integrating moving vehicles for acoustic tomography applications
Authors: Huang Chen-Fen , Taniguchi Naokazu
Published: November 2016

Coastal seas around Taiwan exhibit a wide variety of oceanographic processes associated with the complex bottom topography, tides, winds (monsoons and typhoons), the Kuroshio, and the others. Conventional oceanographic measurements (e.g., acoustic Doppler current profiler) do not provide a synoptic image of the dynamic processes unless a large number of instruments are deployed. Ocean Acoustic Tomography (OAT) is an effective method for mapping the time-evolving spatial distribution of ocean current and temperature. As illustrated by Cornuell et al. (1989), the small spatial scale of ocean features is resolved by incorporating a ship-towed transceiver to the moored transceiver array, referred to as moving ship tomography (MST). The MST technique is applied to the ocean current reconstruction in coastal seas around Taiwan and is extended by using an autonomous underwater vehicle (AUV) as an alternative carrier for the transceiver. This talk presents a brief summary of the recent experiments and our upcoming project. Included are 1) a series of current-mapping experiments integrating moving vehicles in shallow-water environments and 2) simulation study of MST for experiment design on mapping the Kuroshio-induced current wakes of Green Island southeast of Taiwan.
Ocean gliders as tools for acoustic tomography
Authors: Van Uffelen Lora J. , Webster Sarah E. , Lee Craig M. , Gobat Jason I. , Worcester Peter F. , Dzieciuch Matthew A.
Published: November 2016

Ocean gliders are capable and increasingly ubiquitous platforms for collecting oceanographic data such as temperature and salinity measurements. These data alone are useful for ocean acoustic tomography applications, but gliders equipped with acoustic receivers can also record transmissions from acoustic sources, potentially providing additional paths for tomographic inversions. There are challenges associated with the use of gliders as tomography receivers, however, notably the uncertainty in underwater glider position, which can lead to ambiguity between sound-speed and glider position. Glider-based acoustic receptions from moored tomography sources can provide range measurements to aid in subsea glider localization. These data can be used in post-processing for precise glider positioning and in real-time for glider navigation. The current state of the art will be reviewed, and preliminary results will be presented from an experiment in the Arctic Ocean, which seeks to use moored acoustic tomography source signals for both subsea glider positioning and real-time navigation, including navigation under ice. [Work sponsored by ONR.]
Moving ship tomography experiments in a coastal sea
Authors: Taniguchi Naokazu , Li Yun-Wen , Huang Chen-Fen
Published: November 2016

This study considers measuring differential travel times (DTT) between moored and ship-towed transceivers in shallow waters as a feasibility study to extend the concept of the moving ship tomography (Cornuelle et al., 1989) to current field reconstructions. The delay-Doppler ambiguity function (AF) method is used to estimate and compensate the waveform distortions induced by the relative motion between transceivers. The Doppler shift (the relative speed between transceivers) is estimated by the peak of the AF, and the delay time series associated with the peak is the Doppler compensated arrival pattern. The DTTs are determined using the compensated arrival patterns in reciprocal directions. For the current estimation the estimated relative speed is used for removing the effect of the transceiver motion from the DTTs. A reciprocal sound transmission experiment was conducted using a ship-towed transceiver and two moored transceivers in the Sizihwan coastal near Kaohsiung, Taiwan. Due to the complicated arrival patterns observed, the DTTs were determined by tracking the peaks of the cross-correlation functions between the compensated reciprocal arrival patterns over the transmissions. The path-averaged currents derived from DTT agreed well with the direct measurement using a bottom-mounted acoustic Doppler current profiler.
Acoustic observations and characterization of oceanic methane gas bubbles rising from the seabed
Authors: Weber Thomas C.
Published: November 2016

Methane, a potent greenhouse gas, can be found escaping the ocean seabed as gas bubbles in a wide range of geographic locations and water depths. As they rise toward the sea surface, methane gas bubbles undergo a complicated evolution. During ascent, methane gas is transferred into aqueous solution and other dissolved gases are transferred into the bubble. The gas transfer rate—a key factor in determining the ultimate fate of the methane—may be inhibited by hydrate formation in deep, cold water, or potentially by surfactants and adsorbed particulates at any depth. The presence of methane gas bubbles from both natural and anthropogenic sources is often identified using acoustic echo sounders. Beyond simple detection, acoustic techniques can be used to characterize methane bubbles in several ways. For example, narrow-band observations of seep target strength can be used with knowledge of bubble size distributions to estimate methane flux. Similar acoustic observations can be coupled with bubble-evolution models to constrain the fate of bubbles as they rise. Broadband techniques offer the potential to directly observe bubble size and rise speed, and consequently depth-dependent gas flux. The application of these and other techniques for detecting and characterizing methane gas-bubble seeps will be discussed.
Recent advances in resonant ultrasound spectroscopy to measure bone stiffness tensor
Authors: Grimal Quentin , Cai Xiran , Peralta Laura , Xu Kailiang , Marrelec Guillaume , Daoui Hassiba , Laugier Pascal
Published: November 2016

Resonant Ultrasound Spectroscopy (RUS) is a method to measure the elasticity tensor of a material. RUS is particularly advantageous to measure small samples of anisotropic materials. In RUS, resonant frequencies of a sample are measured and computed frequencies of a numerical model of the sample are fitted, yielding the stiffness tensor. RUS was developed in the 1990s, but until recently, it was in practice limited to measure materials with a high quality factor. We have adapted the method to measure bone whose quality factor is about 25. Our strategy combines Bayesian methods to retrieve overlapped resonant peaks in the RUS spectra and to solve the inverse problem using a limited number of resonant frequencies. The method allows a quasi-automated processing of RUS spectra where it is not necessary to know a priori the pairing between measured and computed frequencies. In the last years we have extensively used RUS to document the anisotropic elastic properties of human cortical bone and to investigate the determinants of elastic properties. We present in this talk 1) recent advances in signal processing for RUS; 2) a discussion on the precision of bone elasticity measurement; and 3) a new perspective regarding cortical bone elasticity determinants.
Passive twin-layer spatial-temporal phase-interference compensator for improved transcranial ultrasound propagation
Authors: Langton Christian M.
Published: November 2016

Transcranial ultrasound wave degradation created by variations in both thickness and tissue composition is a significant impediment to diagnostic and therapeutic interventions of the brain. The current “active” solution is to vary the transmission delay of ultrasound pulses, inherently necessitating electronic control of each individual transducer element. By applying the sonic-ray concept of ultrasound wave propagation, it was hypothesised that wave degradation can be significantly reduced if both the transit-time and propagation path-length for all sonic-rays are made constant. A computer simulation study was performed to investigate the implications of zero, partial and full spatial-temporal matching. Considering ultrasound propagation through a 20-step acrylic wedge test sample, only full spatial-temporal matching removed phase-interference. A “passive” physical ultrasound phase-interference compensator (UPIC), consisting of two layered materials of variable thickness, was developed and experimentally evaluated using acrylic step-wedge test samples exhibiting varying degrees of transit-time heterogeneity induced phase-interference. Time- and frequency-domain analysis demonstrated that incorporation of the UPIC successfully removed phase-interference in all cases. It is further hypothesised that the UPIC concept may be applied to both pulse-echo mode diagnostic imaging and transmission mode therapeutic interventions, incorporating either a single-element or a multi-element array transducer, of any practicable dimension.
Is there a role for approximations to the Kramers-Kronig relations in understanding the propagation of ultrasound in bone?
Authors: Miller James G.
Published: November 2016

Clinical measurements of the speed of sound (SOS) usually exhibit moderately large site-to-site variations within a given individual, leading to rather wide ranges for osteoporosis, osteopenia, and normal. Consequently, the rather modest variation of phase velocity over 200 kHz to 800 kHz predicted by the approximate form of the Kramers-Kronig relations developed in our laboratory would appear to be of limited interest. However, whereas the Kramers-Kronig relations predict a systematic increase in phase velocity with frequency, laboratories in Kyoto, Paris, and Washington, D.C., each reported a systematic decrease in phase velocity with increasing frequency. We suggested that this “anomalous” (negative) decrease in velocity with frequency was actually the consequence of interference between two waves, each of which satisfied the Kramers-Kronig-predicted positive dispersion, with one wave sufficiently stronger than the other that the combination appeared to be only a single wave. Although separation of the fast and slow waves by Bayesian, Prony’s, and other methods has provided substantial insight, significant unexplained results remain and are a focus of this presentation. The author wishes to acknowledge significant contributions by former colleagues: C. Anderson, A. Bauer, G. Brandenburger, L. Bretthorst, A. Groopman, J. Hoffman, S. Handley, M. Holland, M. Hughes, E. Jaynes, J. Katz, K. Marutyan, J. Mobley, R. Norberg, M. O’Donnell, R. Trousil, and K. Waters.
Signal processing methods for through-transmission measurements of fast and slow waves in bovine and equine cancellous bone
Authors: Wear Keith A. , Groopman Amber , Katz Jonathan , Holland Mark , Nagatani Yoshiki , Mizuno Katsunori , Matsukawa Mami , Miller James G.
Published: November 2016

Through-transmission measurements in cancellous bone in vitro often reveal two longitudinal waves. The velocities and amplitudes of fast and slow waves are related to bone microstructure and composition and may provide useful diagnostic information. Phase velocity and attenuation for fast and slow waves were measured as a function of propagation depth in bovine and equine cancellous bone. Ultrasound measurements were performed as the thicknesses of bone samples were systematically reduced from 15 to 6 mm (bovine) or 12 to 4 mm (equine) (Nagatani et al., Ultrasonics, 48, 607-612, 2008). Fast and slow wave properties were estimated using a Bayesian method (Marutyan et al., J. Acoust. Soc. Am., 121, EL8-EL15, 2007) and the modified least-squares Prony’s method with curve fitting (Wear, J. Acoust. Soc. Am.,133, 2490-2501, 2013). The two methods, although based on different sets of assumptions, showed excellent agreement. This work provides strong support for both algorithms and for the two-wave model for cancellous bone upon which both are based (Marutyan et al., J. Acoust. Soc. Am., 120, EL55-EL61, 2006).
Phase cancellation effect on broadband ultrasonic attenuation analysis for human trabecular bone assessment using a 2-D synthetic array
Authors: Qin Yi-Xian , Cheng Jiqi
Published: November 2016

Quantitative ultrasound has been developed to evaluate trabecular BMD and structural integrity. The ultrasound parameters, i.e., normalized broadband attenuation (nBUA), have been widely used for bone health status. However, the reproducibility and accuracy of nBUA are influenced by the phenomena of phase cancellation. The objectives of this study have two folds, 1) to accurately investigate the effects of phase cancellation on BUA calculation using an ultra-small receiver (aperture size: 0.2 mm) in a newly developed 2-D synthetic array-system, and 2) to evaluate the effects of phase cancellation on human trabecular bones. Most energy was located within a circle with a diameter of 12.70 mm corresponding to the transmitter aperture size. The tests of ultrasound BUA and micro-CT on the trabecular bone cylinders with a diameter of 25 mm. Both phase sensitive (PS) detection and phase insensitive (PI) detections were performed. The data indicated that the average nBUA is 24.8±9.5 dB/MHz/cm and 19.2±5.5 dB/MHz/cm for PS and PI respectively. PS nBUA is 28.5% higher than PI BUA, which PS-nBUA can explain 81.2% of the variability in PI nBUA. Both PI-nBUA and PS-nBUA are highly correlated with BV/TV (R = 0.911 and R = 0.898, p<0.0001), and the Young’s modulus (R = 0.9061 and R = 0.822 p<0.0001), respectively.
Structure-function relationship in bone: Anisotropic mechanical properties of trabecular bone determined using poroelastic ultrasound
Authors: Cardoso Luis
Published: November 2016

In the ageing skeleton, trabecular bone adapts its porosity, microarchitecture, and tissue composition in response to its mechanical environment through a complex and well-orchestrated bone remodeling process. Such adaptation process allows bone to be mechanically competent to resist low-trauma fractures. However, the relationship between structure and function in bone is not yet fully known. To take into account the effect of anisotropic architecture on the mechanical properties of porous media, the fabric tensor F was introduced in bone Biomechanics by Cowin. The fabric tensor F is a quantitative stereological measure of the degree of structural anisotropy and the mechanical principal orientations of a porous medium. We recently incorporated the fabric tensor into the theory of wave propagation in a fluid saturated porous media, and showed that the fabric tensor is a good predictor of directional-dependent measurements of ultrasound in cancellous bone. In our current study, we demonstrate that the spatial distribution of mass and pore space in trabecular bone (i.e., fabric), when combined with its volume fraction and tissue mineral density, is able to well describe the directional-dependent variability of the anisotropic elastic and yield behavior of bone, which cannot predicted by bone mineral density alone.
Healing and the immune response following boiling histotripsy ablation of renal carcinoma in the Eker rat
Authors: Schade George R. , Wang Yak-Nam , Gravelle Kayla , Whang Stella , Pillarisetty Venu , Hwang Joo Ha , Liles W. Conrad , Khokhlova Vera , Bailey Michael R. , Khokhlova Tatiana D.
Published: November 2016

Boiling histotripsy (BH) is an experimental non-invasive focused ultrasound (FUS) technology that uses milliseconds-long ultrasound pulses at low duty cycle to mechanically homogenize targeted tissue. Here, we report the evolution of BH lesions and the resulting immune response to in vivoablation of renal carcinoma (RCC) in a rat model. RCC bearing Eker rats and syngeneic wild-type rats were randomly assigned to transcutaneous BH or FUS SHAM procedure targeting ~0.5 cc of RCC or non-tumor bearing normal kidney. BH was delivered with a 1.5 MHz US-guided small animal FUS system (VIFU-2000, Alpinion) operated at duty cycles of 1-2%, 10-20 ms pulses, and 525-600 W electric power. Rats were survived for up to 56 days post-treatment. BH lesions evolved from sharply demarcated regions of homogenized tissue to small fibrous scars by 56 days. Compared to sham procedure, BH produced significant alterations in plasma and intrarenal cytokines and tumor/renal infiltrating leukocyte populations. These data describe the immunologic changes and time course of healing following BH ablation in vivo. Future studies will further address tumor control and the impact on metastases. [The Focused Ultrasound Foundation, The Urology Care Foundation, and NIH K01EB015745 and R01CA154451.]
A method for phase aberration correction of high intensity focused ultrasound fields using acoustic nonlinearity
Authors: Khokhlova Tatiana , Maxwell Adam , Kreider Wayne , Khokhlova Vera , O'Donnell Matthew , Sapozhnikov Oleg
Published: November 2016

High intensity focused ultrasound (HIFU) therapies are often affected by aberrations induced by soft tissue heterogeneities. To mitigate these aberrations, phase corrections at different elements of a HIFU transducer array can be introduced, if suitable feedback is available. Existing feedback approaches include maximization of focal tissue displacement induced by acoustic radiation force or scattering from a cavitation bubble nucleated at the focus. Here we propose an aberration correction method based on backscattering of strongly nonlinear HIFU waves that are present only at the focus. A 1.5 MHz, 12-element sector array was integrated with a coaxially aligned imaging probe (P7-4). Each element of the array emitted a short, high-amplitude pulse through the aberrative layer toward the focus in tissue, and the imaging probe recorded the backscattered signal at higher frequencies. The focusing gain of each sector element was sufficient to generate a highly nonlinear focal waveform, which allowed localizing the “beacon” for phase correction feedback. The relative transmit time delays for array elements were calculated based on cross-correlations between the nonlinear backscattered signals corresponding to the other elements. The results of hydrophone measurements and ex vivo tissue experiments demonstrate the feasibility of the proposed approach. [Work was supported by NIH K01EB015745 and R01EB7643.]
Effects of temperature on the histotripsy intrinsic threshold for cavitation
Authors: Vlaisavljevich Eli , Xu Zhen , Maxwell Adam , Mancia Lauren , Zhang Xi , Lin Kuang-Wei , Duryea Alexander , Sukovich Jonathan , Hall Tim , Johnsen Eric , Cain Charles
Published: November 2016

A histotripsy cavitation cloud can be formed by a single acoustic pulse with one high amplitude negative cycle, when the negative pressure exceeds a threshold intrinsic to the medium. The intrinsic threshold in water-based soft tissues, which is similar to the intrinsic threshold of water, has been experimentally verified in the range of 24-30 MPa over a frequency range of 0.3-3 MHz at 20°C. In this study, the effects of temperature on the intrinsic threshold was investigated both experimentally and theoretically. Single pulses with one high amplitude negative cycle at 1 MHz were applied to distilled, degassed water at temperatures ranging from 10°C-90°C. Cavitation was detected and characterized by passive cavitation detection and high-speed photography, from which the probability of cavitation was measured vs. pressure amplitude. The results indicated that the intrinsic threshold significantly decreases with increasing temperature, showing a nearly linear decreasing trend from 29.8±0.4 MPa at 10˚C to 14.9±1.4 MPa at 90˚C. Overall, this study supports our hypothesis that the intrinsic threshold is highly dependent upon the temperature of the medium, which may allow for better predictions of cavitation generation at body temperature in vivo and at the elevated temperatures commonly seen in high intensity focused ultrasound (HIFU) regimes.
A nanotube thermophone projector array
Authors: Dzikowicz Benjamin , Tressler James F. , Baldwin Jeffery W.
Published: November 2016

Thermophone projectors fabricated using newly available nanoscale materials as elements hold the promise of a new transducer technology for the Navy. With no moving parts, they can operate over a broad frequency range and can be designed to be lighter and thinner than competing technologies. Scaling arguments and numerical models are explored to understand the parameter space for a gas-enclosed thermophone applicable to micro- and nanoscale elements. These models led to the development of an element made from a sparse horizontal array of single-walled nanotubes. Experiments are performed in NRL’s Laboratory for Structural Acoustics using a specifically designed enclosure for underwater operations. Results and analysis of experiments using various fill gasses and internal pressures will be presented. [Work supported by NRL.]
Hydrophone calibration system
Authors: Biber Alper , Corakci Ata C.
Published: November 2016

A system to calibrate underwater electro-acoustic hydrophones by primary method, namely, Reciprocity method, in wide frequency range from few kilohertz to megahertz is presented. The aim is to realize primary level “Hydrophone Calibration System” covering from few kilohertz to upper limit of underwater applications with very limited restrictions in one simple system. This system not only covers wide frequency range of underwater applications but also offers low-cost solution to reach enough uncertainty level required for primary calibration according to standards [1]-[3]. The system is based on very high resolution PC oscilloscope of Pico Technology, namely, PicoScope 4262, used for primary data acquizition and digitizing. Primary signal generator and power amplifier, available in market, are integrated into system for purpose. The detailed description is presented and uncertainty budget is discussed.
Comparison of computational schemes in the design of a large-scale projector array
Authors: Noh Eunghwy , Chun Wonjong , Ohm Won-Suk , Chang Woosuk , Youn Hongwoo
Published: November 2016

Modeling and simulation for the design of a projector array involves computations in the transducer and acoustic domains. In the transducer domain, each transducer is often described by the two-port, equivalent-circuit model, in which the radiation impedance containing the influence of the neighboring transducers as well as the medium is not known a priori. To obtain the radiation impedance and the subsequent transducer response a set of coupled transducer equations must be solved simultaneously in conjunction with the (computationally expensive) wave-field calculation in the acoustic domain. In this talk, we compare two computational schemes for speed, which differ in the way the mutual interaction of transducers is treated: the first scheme explicitly accounts for the mutual interaction in terms of the mutual impedance, whereas in the second scheme the interaction is reflected implicitly in the iterative solution of the transducer equations. Here, the speed is largely determined by the number of wave-field calculations required for the desired accuracy. Comparison is made for the case of a cylindrical array of 288 tonpilz transducers. [This work was sponsored by LIG Nex1 Co., Ltd.]
Smart loop sequencer: An audio-based approach for ease of music creation
Authors: Kitahara Tetsuro
Published: November 2016

A loop sequencer is expected to be a good tool for non-musicians to compose music. However, it is not easy to appropriately select music loops because a loop sequencer usually has a large scale of loop collection. In this paper, we propose a smart loop sequencer that automatically selects music loops based on the degree of excitement input by the user. The user expresses a temporal evolution of a desired excitement as a continous curve using the mouse of the PC. Then, the system searches for a sequence of music loops that generates the most similar excitement to the user's input. This process is formulated with a hidden Markov model (HMM). A combination of music loops is regarded as a state of the HMM, and an excitement input by the user is regarded as an emission value. Given a sequence of excitement, the most likely combination of music loops for every measure is estimated with the Viterbi algorithm. Experimental results show that non-experts of music easily compose musical pieces with our system.
Activity disturbances caused by Shinkansen railway noises through the meta-analysis in Japan
Authors: Morihara Takashi , Yokoshima Shigenori , Yano Takashi
Published: November 2016

More than 50 years have passed since the Tokaido Shinkansen railway, the first high-speed railway, opened in 1964. The network of Shinkansen lines has been continuously expanded in Japan: the Hokuriku and Hokkaido Shinkansen lines were partially opened in 2015 and 2016, respectively. To preserve the living environment and to protect human health, the Japanese government enacted the Environmental Quality Standards for Shinkansen Superexpress Railway Noise in 1975. Many social surveys on community response to Shinkansen railway noise and vibration have been conducted. A part of these surveys data have been accumulated in Socio-Acoustic Survey Data Archive. We reanalyzed data from seven social surveys along six Shinkansen lines carried out from 1995 to 2013. The number of response to the question of daily activities was from 5441 to 1997 samples. TV/radio listening disturbance was greater than other listening disturbances at the same noise level. The evaluation of awakening exceeded 10% above the night time noise level of about 45 dB. Through the comparison between the survey, it was indicated that the effect of differences in the number of train service per day.
Community response to transportation noises in Japan: Secondary analysis using the Japanese socio-acoustic survey data archive
Authors: Yokoshima Shigenori , Morinaga Makoto , Yano Takashi , Morihara Takashi , Kawai Keiji
Published: November 2016

A number of socio-acoustic surveys on community response to transportation noises have been carried out in Japan since 1970s. The findings from early precious surveys contributed to the establishment of Noise Regulation Law and Environmental Quality Standards regarding noises. However, micro datasets consisting of noise exposure and reactions to noise from recent studies have yet to be accumulated into a unified system. Dose-response relationships obtained through re-analysis of micro-data form the basis of the progress of effective noise policies. Thus, the Japanese Government faces many difficulties in reviewing noise policies. To develop an archive of community responses to noise, we established the Japanese Socio-Acoustic Survey Data Archive (J-SASDA) and have started the secondary analysis since 2011. In this presentation, we introduce the outcomes of our activity. First, we compare exposure-annoyance relationships among the modes of transportation using the J-SASDA and determine the curves per mode of transportation. Next, we focus on the comparison of exposure-annoyance relationships for transportation noises among European and American countries, Vietnam and Japan. Finally, we intend to establish the Asian-SASDA (A-SASDA) in collaboration with researchers from neighboring Asian countries and explain the current status and problem.
Transportation noise: Nuisance or disability?
Authors: Bristow Abigail
Published: November 2016

This paper reviews the state of the art with respect to the valuation of transportation noise nuisance. It considers recent movements away from values based on revealed or stated preferences (SP) to values based on disability weights. Posing the question as to whether the experience of noise nuisance constitutes a disability. Environmental noise imposes amenity losses and adverse health outcomes on the population. As the world becomes more urban, increasingly motorized and aviation growth persists, noise nuisance is likely to affect ever more people. In identifying and prioritising interventions to reduce experienced noise, it is essential to identify the benefits not just in terms of decibel reductions but in terms of the economic benefits of achieving such changes so these may be compared with costs of interventions to ensure best value for money. The values from a recent meta-analysis of SP studies are compared with those derived using the more conventional hedonic pricing (HP) approach including meta-analyses of HP studies of aircraft noise and more recent developments with respect to assessing annoyance in the form of disability adjusted life years (DALYS) and applying a value of a quality adjusted life year (QALY) to this.
Probability of receiving a blast noise complaint based on population density
Authors: Morrison Dawn A. , Gonzalez Jose M. , Nykaza Edward T.
Published: November 2016

This study extends previous work done by Nykaza et al. (2012) on the probability of receiving a blast noise complaint to include population density in the analysis. Nykaza et al. specifically asked, “what is the probability of receiving a blast noise complaint on a given day within 5 km of a noise monitor?” The original study examined 102,116 blast events and 148 complaints recorded over 641 study days around one military installation. Results from the original study found that while the overall probability of receiving a blast noise complaint was very low, blast noise complaint tolerances around individual noise monitors varied significantly. The current study combines dasymetric mapping techniques—an overlay method for redistributing arbitrarily organized data based on real world circumstances—and regression analysis to examine the different complaint tolerances, and explores what role, if any, characteristics of surrounding population may play in determining the probability of receiving a blast noise complaint. The results indicate that population density has a direct relationship with blast noise complaint tolerance and suggest that population density may be used as a proxy variable in noise complaint forecasting models.
Liftoff and time equivalent duration data evaluation of exploration flight test 1 Orion multi-purpose crew vehicle
Authors: Houston Janice
Published: November 2016

The liftoff phase induces high acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are used in the prediction of the internal vibration responses of the vehicle and components. There arises the question about time equivalent (Teq) duration of the liftoff phase and similarity to other launch vehicles. Vibroacoustic engineers require the fatigue-weighted time duration values for qualification testing inputs. In order to determine the Teq for the Space Launch System, NASA’s newest launch vehicle, the external microphone data from the Exploration Flight Test 1 (EFT-1) flight of the Orion Multi-Purpose Crew Vehicle (MPCV) was evaluated. During that evaluation, a trend was observed in the data, and the origin of that trend is discussed in this paper. Finally, the Teq values for the EFT-1 Orion MPCV are presented.
Azimuthal coherence of the sound field in the vicinity of a high performance military aircraft
Authors: Leete Kevin M. , Wall Alan T. , Gee Kent L. , Neilsen Tracianne B. , Harker Blaine M. , James Michael M.
Published: November 2016

Mixing noise from a jet engine originates from an extended spatial region downstream of the nozzle and is partially correlated both spatially and temporally. Previously, the coherence properties in the downstream (axial) direction of the sound field of a tethered military aircraft were investigated, resulting in the identification of different spatial regions based on coherence length [B. M. Harker et al., AIAA J. 54, 1551-1566 (2016)]. In this study, a vertical array of microphones to the side of the jet plume is used to obtain the azimuthal coherence of the sound field. Although multipath interference effects and a limited angular aperture make coherence length calculation impossible, information about upper and lower bounds can be extracted. The measured azimuthal coherence as a function of downstream distance and frequency is then compared to that predicted by sound field reconstructions using multisource, statistically optimized near-field acoustical holography (M-SONAH) [A. T. Wall et al., J. Acoust. Soc. Am., 139, 1938-1950 (2016)]. This comparison helps to benchmark the performance of a reduced-order M-SONAH algorithm that employs only axisymmetric cylindrical basis functions to represent the direct and image sound fields. [Work supported by USAFRL through ORISE (2016).]
Speech intelligibility by bilateral cochlear implant users when interaural level cues are made more consistent across frequency
Authors: Brown Christopher
Published: November 2016

Interaural level differences (ILDs) aid speech understanding for listeners with both normal hearing (NH) and bilateral cochlear implants (BCIs). Naturally-occurring ILDs are less than ideal for this outcome; however, as they are generally restricted to frequencies above about 2000 Hz, while the energy in speech is typically concentrated below 2 kHz. It has recently been demonstrated that applying larger-than-normal ILDs in the low-frequency region can significantly improve speech intelligibility for BCI users. Despite the benefit, this may result in sound sources that appear to move, depending on where in frequency the speech energy resides at a given moment. The current study examined the effect of applying larger-than-normal ILDs both above and below 2 kHz. Speech intelligibility was measured in simulation by 16 individuals with NH, and by eight BCI users, of a target talker along the midsagittal plane in the presence of symmetrically placed masker talkers on either side. An improvement of about 20 percentage points was observed at a number of masker locations for both populations tested when larger-than-normal ILDs were extended into the high-frequency region, although perceptual movement of sound sources appeared to be more noticeable for the NH group. [Work supported by the NIDCD.]
Uncertainty in binaural hearing linked to inherent envelope fluctuations
Authors: O'Brien Gabrielle , Winn Matthew
Published: November 2016

It was recently shown that supra-threshold changes in interaural level differences (ILDs) in 1/3-octave bands of noise were more quickly and reliably perceived when carried by high-frequency (4000 Hz) rather than low-frequency (500 Hz) noise. For fixed-octave ratio noises, however, center frequency differences are accompanied by differences in inherent envelope modulations stemming from differences in absolute bandwidth. We propose that envelope fluctuations (rather than frequency differences) are a more parsimonious explanation of response latency and certainty. In the current study we investigate the hypothesis that for noisier envelopes, there is less certainty that an ILD is a true diversion from noise perceived at center. Differences in inherent envelope modulation strength were controlled using three types of stimuli: low-noise noise (with negligible envelope fluctuations), high-noise noise, and an equal mixture of the two. Perception of ILD changes was measured using anticipatory eye movements elicited by ILD changes. Results confirm that sensitivity and response latency to ILD changes were affected by degree of envelope fluctuation. In addition, high-noise noise provoked more phantom percepts, which were nearly absent for low-noise noise. Finally, we propose a mathematical model of accumulating certainty in this task as a function of time and degree of envelope fluctuation.
Front-back sound source localization confusions when sources and listeners are rotated
Authors: Yost William
Published: November 2016

Sound source localization identification judgments were made in the azimuth plane with the goal of determining front-back and back-front confusions. The sounds were filtered 125-ms noise bursts: two and 1/10th octave wide at center frequencies of 500 and 4000 Hz, and a wideband (125-8000 Hz) condition. Sounds were either presented from one of six evenly spaced (60o) random loudspeaker locations (random) or the sound presentation rotated clockwise (rotating) around the six loudspeaker array except on 20% of the trials when the location of the loudspeaker was randomly determined. Four conditions were tested: Listener Stationary with Eyes Open (L-O), Listener Stationary with Eyes Closed (L-C), Listener Rotating with Eyes Open (R-O), and Listener Rotating with Eyes Closed (R-C). Listener rotation was clockwise at 45o/s. Localization accuracy and the type of errors, especially front-back and back-front errors, were determined for 18 normal hearing listeners. Sound source localization accuracy and the number of front-back and back-front confusions varied as a function of the different filtered noises, the type of sound source presentation (random or rotating) and the listening condition (L-O,L-C,R-O,R-C). There were very large individual differences, especially in front-back and back-front confusions. [Work supported by Grants from AFOSR and NIH.]
Audiometrically-defined “slight” or “hidden” hearing losses can be manifested as changes in binaural detection
Authors: Bernstein Leslie R. , Trahiotis Constantine
Published: November 2016

We hypothesized that audiometrically-defined “slight” or “hidden” hearing losses might be associated with losses in binaural detection via degradations in precision of coding of interaural temporal disparities (ITDs). Thirty-one listeners were tested using masking configurations that, taken together, allow one to describe how precision of ITD-coding varies as a function of reference ITD and center frequency. Binaural detection thresholds at 500 Hz and 4 kHz were found to increase magnitude of ITD, consistent with there being a loss of precision of ITD-coding that increases with magnitude of ITD. Binaural detection thresholds were elevated, across all ITDs, for those listeners whose absolute thresholds at 4 kHz exceeded 7.5 dB HL, but were not greater than 23 dB HL. No such elevations were observed in conditions having no binaural cues available to aid detection (i.e., “monaural” conditions). Partitioning and analyses of the data revealed the elevated thresholds: 1) were more attributable to hearing level than to age; 2) result from increased levels of internal binaural-processing noise. Our conclusion is that listeners whose high-frequency monaural hearing status would be classified audiometrically as being normal or “slight loss” could still suffer from perceptually meaningful losses of binaural processing.
Reverberation enhances the relative potency of onset cues for sound localization
Authors: Stecker G. C. , Nihal Asawer , Stecker Julie M. , Moore Travis M.
Published: November 2016

Onset dominance in spatial hearing has been repeatedly demonstrated through studies of the precedence effect, Franssen effect, and temporal weighting in sound localization. Such effects are often cited as evidence that onset dominance enhances spatial perception, particularly in reverberant environments where post-onset cues are degraded by echoes and reverberation. Most studies, however, have presented sounds in anechoic space or via headphones. Thus, the actual effects of reverberation on onset dominance are not well understood. This study adapted the approach of Stecker & Hafter (2002; JASA 112:1046-57) to measure temporal weighting functions (TWF) for freefield localization of Gabor click trains (4 kHz; 200 Hz click rate) in the presence or absence of simulated reverberation. Reverberant conditions simulated a 10m x 10m room with modestly absorptive walls (α = 0.5). For each potential source location, direct sound and all reflections up to 13th order were synthesized at correct azimuths, intensities, and delays. Anechoic conditions presented only direct sound (i.e., source locations were single loudspeakers). Anechoic TWFs revealed modest onset dominance consistent with Stecker & Hafter (2002). Reverberant TWFs exhibited significantly stronger onset dominance. The results suggest a greater role of onsets in real-world listening than previously estimated. [Work supported by NIH R01 DC011548.]
Sound image movement of approaching and retreating sounds
Authors: Hirahara Tatsuya , Okada Shuhei
Published: November 2016

We investigated how listeners perceive sound image movements of moving sound sources horizontally approaching and retreating from a listener’s head under three conditions: directly listening to approaching and retreating real sound sources, listening to binaurally recorded sounds with headphones, and listening to binaurally synthesized sounds with headphones. White noise was emanated from a small loudspeaker put on a slider. The moving directions of the loudspeaker were eight radial horizontal directions at 45° intervals, and the moving distance was 5 to 105 cm from the head. Personal earplug microphones were used for the binaural recording. Personal head-related transfer functions were used to synthesize the binaural signals. Sounds approaching and retreating from listeners’ heads in most radial horizontal directions produced straight approaching and retreating sound images. Those in the 45° and 315° radial horizontal directions, however, yielded anomalous sound image movement. The sound image moved straight forward, bent to the rear as the sound approached, and then followed the same path in reverse as the sound retreated for the real, binaurally recorded, and binaurally synthesized sounds. The analysis of HRTFs suggests that the growth of the inter-aural level difference very close to the head can be the cause of the anomalous sound image movement.
The response of an acoustic trace wavelength enhanced array to an isotropic noise field and optimum processing
Authors: Kirsteins Ivars P. , Cray Benjamin A.
Published: November 2016

Recently, a new array based on generating Bragg-scattered acoustic wavelengths along the surface of an array was proposed (Enhanced directivity with array grating (J. Acoust. Soc. Am. 136 (2), 2014) and Experimental verification of acoustic trace wavelength enhancement (J. Acoust. Soc. Am. 138 (6), 2015)). The technique, denoted acoustic trace wavelength enhancement, relies on embedding periodic structures within an array, chosen to precisely replicate and shift the incident acoustic wavenumber into higher wavenumber regions. In principle, an important advantage of this array over conventional hydrophone-based arrays of the same size is its greatly improved directivity. A prototype array was built and demonstrated in a test tank under idealized high signal-to-noise ratio conditions. However, two important open questions which remain are how this array responds to ambient noise and how to optimally beamform it when multiple signals are present. Using idealized analytical models for the array's plane wave response, we calculate its spatial wavenumber response to an isotropic noise field and investigate instrumentations for optimum beamforming.
Constitutive laws for the design of metallic foam
Authors: Magliula Elizabeth A. , McDaniel James G. , Wixom Andrew S.
Published: November 2016

Cellular materials have recently found attention in structural applications to buffer impacts and for energy absorption. In order to choose the most suitable cellular material based on its intended application, one must understand its mechanical response either through experimentation and/or modeling. Accurate modeling of the response of a material has many advantages, as it helps avoid extensive experimental laboratory tests and provides a fast and efficient avenue to explore the design space and optimize with a specific intent. The problem solved by the present research is as follows: How does one estimate the foam properties, such as porosity and void fraction, to produce a metallic foam with desired mechanical properties, such as Young’s Modulus and Poisson’s ratio? The solution to this problem is vitally important as it will yield an entirely new class of materials with tunable mechanical properties and dramatically improved shock and crack resistance. Therefore, the present work seeks to develop constitutive laws for the design of metallic foams. The resulting semi-analytical micro-mechanical model is applicable to positive Poisson's ratio (PPR), negative Poisson's ratio (NPR) and zero Poisson's ratio (ZPR) metallic foams. It is developed quasi-analytically, implemented numerically, and compared to experimental data for validation.
A helical-structured acoustic metamaterial
Authors: Zhu Jie , Zhu Xuefeng
Published: November 2016

Here, we would like to present a helical-structured acoustic metamaterial that can effectively decelerate sound propagation. Unlike currently avaliable solutions which are mostly dispersive due to the requirement of local resonators., this non-dispersive helical-structured metamaterials is able to provide high effective refractive index. By adjusting the helicity of the acoustic metamaterial structures, we can further modify such refractive index. The performance of this helical-structured acoustic metamaterial has been numerically and experimentally verified. We even designed a lens base on multiple inhomogeneous helical-structured acoustic metamaterial unit cells. This lens can turn normally travelling plane wave into a self-accelerating beam.