bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards automated dementia diagnosis based upon speech
Authors: Sadeghian Roozbeh , Schaffer J. D. , Zahorian Stephen
Published: June 2017

The clinical diagnosis of Alzheimer’s disease and other dementias is very challenging, especially in the early stages. Our hypothesis is that any disease that effects particular brain regions involved in speech production and processing will also leave detectable finger prints in the speech. The goal of this work is an easy-to-use, non-invasive, inexpensive diagnostic test for dementia that can easily be applied in a clinician’s office or even at home. Experimental evidence suggests that strong discrimination between subjects with a diagnosis of probable Alzheimer’s versus matched normal controls can be achieved with a combination of acoustic features from speech, linguistic features extracted from a transcription of the speech, and results of a mini mental state exam. Progress is reported toward a fully automatic speech recognition system tuned for the speech-to-text aspect of this application. In addition to using state-of-the- art automatic speech recognition techniques such as Deep Learning, recurrent neural networks are used to predict the punctuation in transcribed speech, which is later used for extracting linguistic features. This fully automated system for 73 speakers is combined with 140 manually transcribed speech samples and used for experimental testing of a system for automated detection of Alzheimer’s from speech.
Phase correction in extended towed array method
Authors: Wang Yu , Gong ZaiXiao , Zhang Renhe
Published: June 2017

An important issue in research on passive ASW operations is to improve signal-to-noise ratio (SNR) and bearing resolution for targets emitting low frequency signals. Passive Synthetic Aperture Sonar (PSAS) is one of the techniques believed to improve these characteristics. In the past decades, various passive synthetic aperture techniques have been investigated, such as Extended Towed Array Method (ETAM), Fast Fourier Transform Synthetic Aperture (FFTSA), and Maximum Likelihood (ML) algorithm. ETAM is shown to be superior in performance to the other two algorithms. Estimation for phase correction factor is the core idea in original ETAM. Firstly, the cross-correlations of signals on multi-pairs of overlapped hydrophones are estimated, secondly the average value of the cross-correlation phase angles is taken as the least-square estimation for the phase correction factor. However, when the phase angle is close to the discontinuous point, the above estimation method will lead to large estimation error. In this paper, a modified phase correction method in ETAM is proposed, and the discontinuity of phase angle is eliminated to ensure the accuracy of the phase correction estimation. Simulation and experimental results show that the modified method can effectively improve the stability of ETAM.
Passive tracking of autonomous underwater vehicles (AUVs) using a low-cost acoustic data collection system
Authors: Fischell Erin M. , Railey Kristen , Viquez Oscar A. , Schmidt Henrik
Published: June 2017

One challenge to harbor security is monitoring and tracking autonomous underwater vehicle (AUV) activity. A self-contained low-cost acoustic data collection system (acbox) has been developed and demonstrated for this purpose. The acbox consists of an 8-element configurable off-the-shelf hydrophone array, a data acquisition system, a GPS for timing and navigation, and a computer for data logging and processing. Noise data on the Bluefin SandShark and Bluefin 21-inch AUVs were collected using the configurable array in the Charles River and Massachusetts Bay. From this experiment, AUV noise characteristics were determined. The bearing to the AUV was estimated based on beamformed and frequency filtered data, and compared to logged AUV position. The bearing estimates based on propeller noise were consistent with the reported AUV position. These results for range estimation and filtering bearing were tested to provide improved vehicle localization. Performance in the presence of boat noise was also assessed. Moving forward, this work will be expanded to tracking AUVs from other AUVs for collision-avoidence and behavioral analysis for security monitoring applications. [Work supported by Battelle, DARPA, and Draper.]
Characterization and exploitation of lucky scintillations in HLA and VLA data from the 2006 Shallow Water Experiment
Authors: Ge Hongya , Kirsteins Ivars P.
Published: June 2017

The detection and localization of signals using large arrays is challenging in low coherence underwater environments. Poor spatial coherence is a consequence of signal wave front distortions caused by time-dependent three-dimensional spatial fluctuations in the sound speed from internal waves, fronts, and random medium effects such as turbulence. In an earlier paper (Lucky ranging with towed arrays in underwater environments subject to non-stationary spatial coherence loss in Proc. of ICASSP 2016, March 2016) we had proposed a new paradigm for array processing in poor coherence environments, motivated by real data observations, which exploited lucky moments or favorable scintillations when the signal wave front momentarily had little or no distortion. Here we examine the HLA and VLA data from the 2006 Shallow Water Experiment provided by the Woods Hole Oceanographic Institute to better understand and characterize the occurrence of lucky moments or favorable scintillations in actual data and how they can be utilized in array processing. Because of uncertainties in the HLA element positions, we developed a new empirical canonical correlation-based technique for the analysis utilizing lucky moments to blindly estimate the array manifold.
A novel method for cement placement diagnosis behind multiple strings based on sonic dipole cutoff mode processing
Authors: Skataric Maja , Bose Sandip , Zeroug Smaine , Sinha Bikash K.
Published: June 2017

Acoustic measurements are widely used to diagnose the condition and placement of cement in cased oil and gas wells, and its bond to interfaces in contact with it. However current methods, encompassing high frequency sonic CBL-VDL and ultrasonic measurements, are designed for single steel casings and insufficient to probe behind more than one casing, and so cannot address the diagnosis of the placement and bond of cement behind a second casing that have become critical in the oil and gas industry. We therefore look at the use of lower frequency sonic measurements with deeper radial probing capability, to identify features appropriate for such a diagnosis. In particular, in this work we look at the modeling of sonic monopole and dipole modes as generated by existing tools and identify a set of cutoff modes that are indicative of annular fill behind a second casing when the annulus behind the first is known. Therefore the acquisition and processing of such modes in conjunction with the use of traditional cement evaluation techniques could become a viable avenue for the acoustic diagnosis of cement placement in multiple casing string geometries. Modeling results for such scenarios will be presented along with potential application to experimental and field data to indicate the feasibility of such a diagnosis using feature extraction.
Seismic response of fiber optic seismic sensors
Authors: Costley R D. , Hathaway Kent K. , Flynn Darren C. , Galan-Comas Gustavo , Ketcham Stephen A. , Kirkendall Clay K.
Published: June 2017

Fiber-optic seismic sensors (FOSS) consist of an optical fiber connected to an optical interrogator, which is electro-optic instrumentation that injects pulses of coherent light into the fiber and receives and demodulates the returned signals. The optical fiber is usually contained within a protective cable. Experiments were performed on a barrier island setting where several kilometers of cable had been buried at sub-meter depths. It has been hypothesized that seismic disturbances strain a segment of the optical fiber thus causing its optical path length to change. An array of eight 3 axis seismometers were buried alongside the cable at the same depth, with a spacing of 0.5 m, and with one axis parallel to the cable. An electromagnetic shaker, buried at the same depth and in different configurations with respect to the array and the FOSS, was excited with a 10-cycle tone burst varying in frequency from 10 to 200 Hz. The resulting seismic waves were simultaneously recorded with the seismometers and the FOSS. Signals recorded with the seismometer array were processed to calculate the average strain along the direction of the fiber. The presentation illustrates the comparison between the computed strain outputs of the seismometers and that of the FOSS.
Cross-laboratory reproducibility of sound transmission loss testing with the same measurement and installation team
Authors: Shafer Benjamin
Published: June 2017

Previous cross-correlative statistical research studies, combined with the results from past laboratory sound transmission loss round robin testing, illustrate that the laboratory-to-laboratory reproducibility of sound transmission loss testing is inordinately and unacceptably low. Industry building construction professionals use the results of laboratory sound transmission loss testing to determine acoustics-related building code compliance. As such, a forensic analysis of laboratory sound transmission loss is needed to narrow potential causes of cross-laboratory variability to a few primary sources. As a first step in this process, sound transmission loss measurements for two different assemblies are compared between multiple laboratories, each with their own different technicians and installation crews. Two different assemblies are then compared between multiple laboratory facilities with the same measurement and installation crew. The use of the same measurement crew at two different facilities resulted in much better statistical reproducibility than all previous reproducibility studies.
Addressing the lack of statistical control in acoustical testing laboratories
Authors: LoVerde John , Dong David W.
Published: June 2017

In order to be useful in comparing products, evaluating assemblies, or performing research, acoustical laboratory tests must be precise. This means that the “chance” variation due to any external variables must be relatively small and randomly distributed. This defines a measurement method that is in a state of statistical control, in which case the precision of the test method (the size of these small chance variations) can be measured [J. Acoust. Soc. Am. 130, 2355 (2011)]. The authors have observed many airborne and impact insulation tests performed at accredited acoustical laboratories. While controlled behavior is sometimes seen, it is also sometimes observed that a set of results shows unpredictable behavior, abrupt changes, excess scatter, or unexplained variations, which is symptomatic of a loss of statistical control [J. Acoust. Soc. Am. 137, 2216 (2015)]. It is not merely that the precision in the measurement is larger than desired; a lack of statistical control means that there are large unknown variables and the precision of the method cannot even be defined. Experiences with laboratories in which this has occurred are shared, and procedures and safeguards to address the issue are discussed.
Numerical study on the repeatability and reproducibility of laboratory building acoustic measurements
Authors: Dijckmans Arne , De Geetere Lieven , Ingelaere Bart
Published: June 2017

An important issue in building acoustics is the significant variability in laboratory test results that numerous round robin tests have indicated. The current wish to include the frequency bands 50-80 Hz in the procedures to determine single-number quantities has prompted new discussions. In this paper, wave based models are used to numerically investigate the fundamental repeatability and reproducibility. Regarding sound insulation measurements, both the pressure method (ISO 10140-2) and the intensity method (ISO 15186-1 and ISO 15186-3) are investigated in the frequency range 50-200 Hz. Flanking transmission measurements (ISO 10848) are also studied. The investigation includes the repeatability of the different measurement procedures, which depends on the influence of the source and receiver positions. The reproducibility in different test facilities is studied by looking at the influence of geometrical parameters like room and plate dimensions. Increasing the number of source or receiver positions has little effect on the overall uncertainty as the reproducibility uncertainty is generally much larger than the repeatability uncertainty. For small-sized test elements, the reproducibility of the intensity method is better. For heavy walls and lightweight double constructions, however, the predicted uncertainty is similar for the three measurement methods.
Modeling the inhomogeneous reverberant sound field within the acoustic diffusion model: A statistical approach
Authors: Foy Cedric , Valeau Vincent , Picaut Judicaël , FORTIN Nicolas , Sakout Anas , Prax Christian
Published: June 2017

In room acoustics, starting from the sound particle concept, it is now well established that the reverberant field can be modeled from a diffusion equation function of the acoustic density and a gradient equation function of the acoustic intensity. The main works on the development of an acoustic diffusion model have highlighted the major role of a coefficient of the model, the so-called diffusion coefficient. Indeed, the main phenomena influencing the reverberant sound field can be modeled by proposing an appropriate expression of this diffusion coefficient. The work presented here deals with the modeling of inhomogeneous reverberant sound fields induced by geometric disproportions, and investigates, in particular, the case of long rooms. Previously, the ability of the acoustic diffusion to model adequately the spatial variations of the sound field along the room has been demonstrated by considering a diffusion coefficient that is spatially dependent. We propose here to extend this work by determining an empirical law of the diffusion coefficient, depending on both the scattering and absorption coefficients of the walls of the room. The approach proposed here is statistical and is based on the least squares method. Several linear models are proposed, for which a rigorous statistical analysis makes it possible to assess their relevance.
A new method for quantifying binaural decoloration based on parametrically altering spectral modulations
Authors: Haeussler Andreas , van de Par Steven
Published: June 2017

The reproduction of sound in a reverberant environment leads to spectral modifications that are typically perceived as coloration. It is well known that a dichotic instead of a diotic presentation of such signals leads to reduced perception of coloration [Salomon (1995), Ph.D. Thesis, TU Delft]. In this contribution, a new method is presented for quantifying the reduction in coloration due to dichotic presentation. In this method, the first part of a Binaural Room Impulse Response, pre-dominantly responsible for the spectral envelope is extracted, and the spectral modulations are parametrically modified and reinstated on a minimum-phase Impulse Response that is convolved with pink noise and musical instruments and presented diotically to the listeners. Their task is to adaptively adjust the spectral modulations until this diotically presented stimulus sounds equally colored as a dichotically presented binaural signal. Results show that the spectral fluctuations expressed as standard deviations in decibels needs to be reduced by 1-2 dB for the diotic presentation to sound equally colored as the dichotic presentation.
Influence of visual rendering on the acoustic judgments of a theater auralization
Authors: Postma Barteld N. , Katz Brian F.
Published: June 2017

Auralizations have become more prevalent in architectural acoustics. Auralizations in listening tests are typically presented in a uni-modal fashion (audio only). However, in everyday-life one perceives complex multi-modal information. Multi-sensory research has shown that visuals can influence auditory perceptions, such as with the McGurk and ventriloquist effects. However, few studies have investigated the influence of visuals on room acoustic perception. Additionally, in the majority of previous studies, visual cues were represented by photographs either with or without visuals of the source. Previously, a virtual reality framework combining a visible animated source in a virtual room with auralizations was conceived enabling multi-modal assessments. The framework is based on BlenderVR scene graph and visual rendering with MaxMSP for the real-time audio rendering of 3rd order HOA room impulse responses (RIRs) in tracked binaural. CATT-Acoustic TUCT was used to generate the HOA RIRs. Using this framework, two listening tests were carried out: (1) a repeat of a prior audio-only test comparing auralizations with dynamic voice directivity to static orientation and (2) a test comparing dynamic voice auralizations with coherent or incoherent visuals with respect to seating position. Results indicate that judgments of several room acoustic attributes are influenced by the presence of visuals.
Binaural auralization of proposed room modifications based on measured omnidirectional room impulse responses
Authors: Pörschmann Christoph , Stade Philipp
Published: June 2017

The auralization of rooms with dynamic binaural synthesis using binaural room impulse responses (BRIRs) is an established approach in virtual audio. The BRIRs can either be obtained by simulations or by measurements. Up to now changed acoustical properties, as they occur when a room is altered in a renovation, cannot easily be considered in a measurement-based approach. This paper presents a new method to auralize modifications of existing rooms. The authors already have shown in a previous publication that such an auralization can be done by appropriately shaping the reverberation tail of an impulse response. Furthermore, the authors have presented an approach to synthesize BRIRs based on one omnidirectional room impulse response (RIR). In this paper, both methods are combined: A single measured omnidirectional RIR is enhanced and adapted to create a binaural representation of a modified room. A listening experiment has been performed to evaluate the procedure and to investigate differences between synthesized and measured BRIRs. The advantages of this method are obvious: Planned room modifications can be made audible without complex measurements or simulations; just one omnidirectional RIR is required to provide a binaural representation of the desired acoustic treatment.
Music and sound of the 17th Century: Athanasius Kircher and his Phonosophia anacamptica
Authors: Tronchin Lamberto , Knight David J.
Published: June 2017

In the 17th Century many Physicists, Mathematicians and Musicians dealt with the experiences of harmony, music, and sound propagation in enclosed interior spaces. Among them, Athanasius Kircher was one of the most influential researchers of his time. Born in Geisa, Thüringia (Germany), he became a Jesuit in 1608 and spent a large part of his life in Rome, where he died in 1680. During his lifetime, he wrote several books spanning a wide range of topics, including sound, music, and acoustics. One of these, the Phonurgia Nova, published in 1673, was almost ignored for hundreds of years. Phonurgia Nova was translated from the original Latin. It consists of two different books, the Phonosophia nova and the Phonosophia anacamptica. The former deals with the influence of music on human beings whereas the latter analyses sound propagation in enclosed spaces. In this paper, the Authors present new achievements regarding some of the apparatuses that Kircher invented. Among all his marvelous sound machines, the Authors will describe some of Kircher’s items, including the tuba stentorophonica (the “loud trumpet”), the statua citofonica (the “talking statue”), the obiectum phonocampticum (the “phonocentric object”), the Ruota Cembalaria (the “sounding wheel”), the ancient Egyptian singing statue of Memnon, the Aeolian Harp, and the hydraulis (hydraulic organ). Some of these apparatuses were also recently partially realized by the Polish Pavilion during the Biennale of Venice in 2012, achieving a Special Mention from the international jury.
Seeking the sounds of ancient horns
Authors: Campbell D. Murray , GILBERT Joël , Holmes Peter
Published: June 2017

Recent archaeological discoveries, most notably at the Gallo-Roman site at Tintignac in the Corrèze district of France, have thrown fresh light on the nature of some of the lip-excited wind instruments used in Europe around two thousand years ago. In particular, it has been possible to reconstruct working copies of the Celtic horn known as the carnyx, and to experiment on the reproductions both scientifically and musically. A number of Etruscan and classical Roman brasswind instruments, including the lituus and the cornu, have also been reproduced and tested under the auspices of the European Music Archaeology Project. This paper reviews some of this work, and discusses the usefulness of acoustical modeling and measurement in interpreting the possible musical functioning of these ancient horns.
Reconstructing human music with hard evidence
Authors: Atema Jelle
Published: June 2017

Philosophers have long discussed the origins of music and language and used them as an argument to set humans apart from other animals. For evidence we rely on archaeology, anthropology and even biology, and on historical depictions and descriptions. In the case of music we have some hard evidence in the form of ancient bone flutes. Their physical reconstructions are important tools in the quest for origins, but open to interpretation and controversy. As a biologist-flutist I have been skeptical of many resulting “models” that have been proposed. Here I submit some of the main obstacles I encounter in reconstructing 4,000 to 50,000 year-old bone flutes in hopes of hearing their music. How do we define what is a flute? Which physical reconstruction is most credible? Which sounds can it make? Is there a recognizable scale and is that scale credibly constrained? Which sounds constitute music? Is “our” music related to “their” music? While flutes have been preserved in the pre-historic record and their finger holes suggest a musical scale, the oldest evidence is sufficiently weak to allow for many interpretations and vociferous debates. I will demonstrate these questions with a few reconstructions and different types of flutes.
Large scale passive acoustic recording efforts improve our understanding of long term changes in marine mammal ecology and distribution
Authors: Van Parijs Sofie M. , Cholewiak Danielle , Davis Genevieve , Baumgartner Mark F.
Published: June 2017

Collaborative efforts across a large number of scientists working throughout the Western Atlantic Ocean has led to sharing of passive acoustic data spanning over a decade. These data allow for a 24/7 lens to be cast providing a long term temporal understanding of species presence. This collaborative approach has allowed for unprecedented research focusing on long term patterns and changes in distribution and movements of baleen whales and odontocetes. Results from these data shows how baleen whales migration paths can be defined and changes in these paths can be detected over time. Additionally, they show that whales are present at times of the year and in regions that were not previously documented, particularly during winter months. Beaked whale composition within and between each shelf break canyon where recordings are available varies considerably, demonstrating latitudinal as well as regional gradients in species presence. The addition of ambient noise curves to this mix provides context and allows for the evaluation of anthropogenic noise. This long term big picture view of species presence and movements improves our capacity to infer whether observed changes are a result of ecological, climatological, or anthropogenic factors.
Correlation of direct field observations of the endangered Golden Cheeked Warbler (Dendroica chrysoparia) with long-term acoustical measurements
Authors: Wilson Preston S. , Knobles David P. , O’Donnell Lisa , Hutchinson Darrell , Reiner William
Published: June 2017

We present elements of a bioacoustics study that correlated direct field observations of the endangered Golden Cheeked Warbler (Dendroica chrysoparia) in the Balcones Canyonlands Preserve near Austin, TX with co-located long-term acoustical measurements. The goal is to eventually understand the effects of anthropogenic noise on the breeding success of the warblers. The anthropogenic component of the soundscape includes noise from road traffic, jet aircraft, helicopters, and urban development and utilization. During the 2016 and 2017 breeding seasons (March through May), acoustical recordings were made from sun up to sun down each day at four sites. The acoustical measurements were correlated with contemporaneous direct field observations that mapped the male territories and their degree of reproductive success. The study considered the interplay of the source levels of the warblers, the noise, and sound propagation loss in the habitat. The key result is the difference in the distribution of two song types sung by banded birds with different degrees of breeding success. The relationship between these distributions, the corresponding success rates, and the size of the acoustic active space as determined by soundscape characteristics, is discussed.
North Atlantic Right Whale call detection with very deep convolutional neural networks
Authors: Xu Kele , Cai Hengxing , Liu Xi , Gao Zhifeng , Zhang Bingbing
Published: June 2017

Ship collision is one of the main threats to the North Atlantic right whale, which is in danger of extinction. One popular way to reduce the collision is monitoring for the occurrences of whales by detecting their sounds on data recordings. We explore the application of very deep convolutional neural network in this detection problem. For feature extraction, we compute Mel-frequency cepstral coefficients (MFCCs) along with their first and second temporal derivatives, and Fourier-transform-based filter-banks for all sound clips. MFCCs were calculated with Hamming window, and the filter-banks were calculated in range of 50—650 Hz, and include 72 coefficients, distributed on mel-scale, for each of the 97 time steps. For classifier modeling method, we apply the very deep convolutional Neural Network (CNN) in our task. The CNN architecture s 22 layers, which consists of alternating convolutional layer and pooling layer, while the last layers are full-connected neural network. Dropout is used in our fully connected layers with a rate of 0.4. By using the data provided by the Cornell University Whale Detection data, our model provides area under the ROC curve (AUC) performance of 0.985, which achieves the state-of-the-art performance presently.
Computational acoustics for soundscape ecology: Simulation and normalization
Authors: Graupe Cris
Published: June 2017

One of the major research themes of soundscape ecology is to understand ecosystem dynamics by measuring and analyzing patterns in biological acoustic communication in the context of the local environment. The emerging field focuses at landscape scales to quantify compositional, spatial, and temporal variation in these patterns. This is reflected by variation in specific acoustic qualities that must be taken into account to more accurately compare diverse soundscape recordings. A new software is being developed that aims to overcome this challenge. The MATLAB-based software utilizes geometrical and parabolic methods of computational acoustics to simulate terrestrial sound propagation, quantifying the impact of variable environmental filtration on acoustic recordings. This software provides both the ability to quantitatively compare this impact across ecosystems, and the ability to normalize acoustic recordings so that soundscape data from distinct environments can be compared and analyzed more accurately.
Forty years of progress in multibeam echosounder technology for ocean investigation
Authors: Lurton Xavier
Published: June 2017

Along four decades, multibeam echosounders (MBES) have continuously progressed in their technology and application fields, and are today the favorite active sonar tool of several communities for ocean investigation. Measurement capabilities extended progressively from seafloor bathymetry to interface imagery and reflectometry, and to water column imaging and target quantification; the concerned domains spread from hydrography and seafloor-mapping to geosciences, offshore industry, biology and fisheries, coastal engineering, habitat mapping, environmental science and monitoring. The paper proposes an overview of this history, based on the experience of the author’s oceanography institute since 1977. Technologically MBES first extended the classical single-beam echosounder toward a narrow fan of elementary beams, then to a wide-coverage design similar to sidecan sonars, to multiple swaths, and to various geometries of 3-D insonification. Various aspects of MBES technology evolution are presented: frequencies and powers; array configuration and beam features; electronics; sounding detection methods; reflectometry techniques. The progress in performance level includes: coverage extent, bathymetry accuracy, resolution, and sampling density; reflectometry reliability; water column data specificities. The importance of ancillary sensors and on-carrier platform installation is emphasized. Recent trends and possible future evolutions are finally presented, as well as some facts related to MBES environmental impact.
Target detection with multisector and multiswath echosounders
Authors: de Moustier Christian
Published: June 2017

Discontinuities in the ensonification pattern of certain multibeam echosounders can hamper the detection of targets in the water column and on the bottom. Such echosounders operate in single or multiswath modes with several independent transmit sectors per swath. Each sector has a unique acoustic frequency band and is steered across and along track to compensate for the vessel’s pitch and yaw and to achieve a specified spatial density of soundings. This sonar geometry is optimized for bathymetry but less favorable for processing and interpretation of acoustic backscatter intensities because the sectors have different acoustic absorption profiles and are disjoint across and along track. This paper presents a method of target detection in the water column that involves frequency- and depth-dependent compensation for transmission loss in each sector, equalization of gains across all the sectors, and adaptive removal of sidelobe interferences. Echo intensities in each sector are then aggregated along track and displayed as signal-to-clutter ratio vs. altitude and distance along track. This technique allows detection of targets that are in the water column between the bottom echo trace and the ring of sidelobe interference—a region that is often deemed “blind” or too noisy for target detection.
High frame rate imaging of microbubble contrast agents
Authors: Tang Mengxing
Published: June 2017

The advent of microbubble contrast agents has transformed the way blood flow and tissue perfusion can be imaged using ultrasound in cardiovascular and oncological applications. The high echogenicity offered by the microbubbles greatly enhances ultrasound echoes from within the blood, making imaging of micro-vascular flow and tissue perfusion possible. Recent advances in high frame rate (HFR) ultrasound, which uses non-focused wave transmission, parallel data acquisition and digital beamforming, enable an imaging frame rate two orders of magnitude higher than the existing line-by-line scanning approach. A combination of HFR ultrasound with microbubble contrast enhanced ultrasound (CEUS) offers new exciting opportunities in imaging with unprecedented resolution and contrast. The HFR allows better tracking of fast moving target such as arterial flow and cardiac motion. Even for slow moving target, by processing the large amount of data afforded by HFR ultrasound significant improvement in image contrast/signal to noise ratio can be gained. We have developed HFR CEUS imaging methodology based on a HFR ultrasound research platform using both linear and phased array probes, and achieved a frame rate of up to tens of thousands of frames per second over multiple centimeter depth. We have demonstrated that HFR CEUS, together with signal processing, significantly improves macro- and micro-vascular flow imaging in vivo.
Subharmonic response of lipid-coated monodisperse microbubbles
Authors: Li Qian , Porter Tyrone M.
Published: June 2017

Subharmonic emissions from lipid-coated microbubbles, which is not radiated by tissues, can be leveraged to improve contrast-enhanced diagnostic ultrasound. In our work, we investigated subharmonic emissions from monodisperse lipid-coated microbubbles under different acoustic pressure and frequencies. First, the resonance frequency of microbubble monodispersion was determined from measured attenuation spectrum. Next, acoustic emissions from the microbubbles were detected by a transducer positioned orthogonal to the excitation transducer. Our study showed that subharmonic emissions were maximized when bubbles were driven at nearly twice the pressure-dependent resonance frequency rather than the linear resonance frequency. We also observed subharmonic emission at low excitation acoustic pressure (< = 30 kPa) for microbubbles coated with densely packed lipid shells, which suggests that minimizing the initial surface tension can enable subharmonic emissions at very low excitation pressures. Further studies were conducted with shells composed of varying lipids to test the influence of shell composition on the initial surface tension and subharmonic emissions. Theoretical simulations were carried out and agreed with the experimental trends. Implications of these results on the use of monodisperse lipid-coated microbubbles for subharmonic imaging will be discussed.
Study of acoustic droplet vaporization using classical nucleation theory
Authors: Kumar Krishna N. , Aliabouzar Mitra , Sarkar Kausik
Published: June 2017

Lipid coated perfluorocarbon (PFC) nanodroplets can be vaporized by an external ultrasound pulse to generate bubbles in situ for tumor imaging and drug delivery. Here we employ classical nucleation theory (CNT) to investigate the acoustical droplet vaporization (ADV), specifically the threshold value of the peak negative pressure required for ADV. The theoretical analysis predicts that the ADV threshold increases with increasing surface tension of the droplet core and frequency of excitation, while it decreases with increasing temperature and droplet size. The predictions are in qualitative agreement with experimental observations. We also estimate and discuss energy required to form critical cluster to argue that nucleation occurs inside the droplet, as was also observed by high-speed camera.
Full 3D dynamic functional ultrasound imaging of neuronal activity in mice
Authors: Rabut Claire , Correia Mafalda , Finel Victor , Deffieux Thomas , Pernot Mathieu , Tanter Mickael
Published: June 2017

Introduction: In vivo neuronal activity imaging is key to understand the mechanisms of complex brain behavior. 2D Functional Ultrasound (fUS) Imaging is a powerful tool for measuring brain activation with high spatiotemporal sampling (80μm, 1 ms) using neurovascular coupling. Here, we demonstrated the proof of concept of in vivo full 3-D fUS and extend the research work toward 3D functional connectivity imaging in mice. Method: A fully programmable 1024-channel ultrasound platform was used to drive 32 x 32 matrix phased arrays (9 MHz central frequency) at ultrafast frame rates (500 volumes per second). Successive plane wave emissions were compounded to produce high sensitivity vascular volumetric images of the brain of anesthetized (Kétamine-Xylazine) and craniotomized mice. Whiskers were alternatively (6 seconds ON/OFF) stimulated during acquisition. Results: High-quality 3D images of cerebral blood volume were obtained and showed the feasibility of task-activated 3D fUS imaging. The activation maps depict the spatiotemporal distribution of the hemodynamic response to whiskers stimulation at high spatial (150μm x 150μm x 150 μm) and temporal resolution (400 ms). Conclusion: We demonstrated for the first time the feasibility of full 3D dynamic functional brain imaging in mice. This paves the way toward a full-fledged neuro-imaging modality of the entire brain using ultrasound.
Feedback control of an active acoustic metamaterial
Authors: Cheer Jordan , Daley Stephen
Published: June 2017

Acoustic metamaterials have recently been of significant interest due to their potential ability to exhibit behavior not found in naturally occurring materials. This extends to the realization of acoustic cloaks, but perhaps of greater industrial impact is their ability to achieve high levels of noise control performance. In particular, previous research has demonstrated the high levels of transmission loss that can be achieved by an array of locally resonant elements. However, these passive metamaterials are inherently limited in performance due to both losses and their static nature. Therefore, there has been an increasing interest in active acoustic metamaterials, which can allow both increased performance and adaptability. Recent work has investigated the integration of active elements into a passive resonator-based metamaterial, and it has been demonstrated using a feedforward control architecture that significant increases in the level and bandwidth of transmission loss are achievable. However, in many practical noise control applications, it is not possible to obtain a time advanced reference signal that is required for a feedforward control implementation. Therefore, this paper will explore the design of a feedback control architecture that is applicable to the active resonator based acoustic metamaterial and demonstrate the potential performance of such a system.
Development of a novel sound pressure level requirement for characterizing noise disturbances from theater and opera stages
Authors: Melnikov Anton , Guettler Marcus , Gatt Monika , Scheffler Michael , Marburg Steffen
Published: June 2017

In theaters or opera houses, the stage elevator is one of the most important machinery elements. It can be used for holding decorations in place and moving them between scenes or providing effects by elevating large decorations or choirs directly in a play. This scenic movement is a crucial situation from a machinery acoustics point of view. To localize and understand the sources of sound from these elevators, suitable experiments can be performed, e.g. sound pressure level (SPL) measurements, experimental and operational modal analysis. From previous measurements, the drive train could be identified as an important sound source. To quantify suitable quality requirements, the SPLs were measured in various theaters throughout Germany. The new key idea was to do the measurements while playing a drama or opera and to evaluate time periods of calm breaks during the play. This procedure published herein, where the masking effect of noises caused by the auditorium listening to a play is taken into account, lead to a new SPL requirement for the noise radiation of the stage machinery of theaters and opera houses. Last but not least, the results of these measurements in different German theaters, are compared and discussed.
Frequency dependence of Fresnel zone plates focus
Authors: Fuster José Miguel , Candelas Pilar , Rubio Constanza , Castiñeira-Ibáñez Sergio , Tarrazó-Serrano Daniel
Published: June 2017

Fresnel zone plates (FZPs) focus waves through constructive interference of diffracted fields. They are used in multiple fields, such as optics, microwave propagation or acoustics, where refractive focusing by conventional lenses is difficult to achieve. FZPs are designed to work and focus at a design frequency. At this frequency, the behavior of the FZP is optimum and focusing at a certain focal length is achieved. In most medical applications using lenses, it is critical to have a fine and dynamic control on the lens focal length. In this work, the variation of the FZP focus parameters when working at operating frequencies different from the design frequency is analyzed, and a focal length control mechanism is proposed. It is shown that the FZP focal length shifts linearly with the operating frequency, becoming a dynamic control parameter that can be useful in many different applications. However, other focusing parameters, such as focal depth and distortion, are also affected by the operating frequency. These parameters establish a limit on the frequency span in which the operating frequency can be shifted, and therefore they restrict the range of focal lengths available with a single FZP.
Influence of the musician’s position on the radiation impedance for transverse and notch flutes
Authors: Ernoult Augustin , de la Cuadra Patricio , Balosso-Bardin Cassandre , FABRE Benoit
Published: June 2017

To play a transverse or notch flute, musicians place their mouth near an open end of the instrument where a sharp edge or labium is the target of the air-jet blown by the musicians. The jet/labium interaction is responsible for generating sound. Musicians can control the geometry of the air-jet during their performance. They can, for example, decrease the distance from their lips to the labium when increasing the pitch. The presence of the musician and the variation of his position while playing modifies the boundary conditions at the opening which, in turn, impacts the passive resonances of the instrument/player system. Flute manufacture adapted empirically to take into account this effect but, until now, it was never systematically quantified. The main goal of this study is to quantify and model the influence of the musician’s presence and his movements as a modification on the radiation impedance of the instrument. Finite element simulations and experimental mockups are implemented and described in order to fit experimental models. Such models are useful as a complement to physical models of flutes as well as to understand the choices made in flute manufacture.
Reed chamber resonances in free reed instruments
Authors: Cottingham James P.
Published: June 2017

Western free reed instruments such as the accordion, harmonica, and harmonium do not normally employ pipe resonators to determine the pitch, but all do feature some sort of reed chamber or cavity in which the reed is mounted. The reed chamber will necessarily have resonances which can affect the tone quality and the pitch, but, since the cavity volumes are small and the resonances have high frequencies, the effects on the reed vibration generally tend to be small. In some cases, however, a resonance of the reed chamber can be close to the vibration frequency of the reed tongue. In this case, the cavity air vibration can become large enough to influence the self-excitation mechanism, possibly interfering with tongue vibration and the resulting musical tone, and in some cases preventing the sounding of the reed at all. For various configurations of the reed chamber, reed motion during the initial transient stage of free reed vibration has been analyzed, exploring effects on the rise time and final amplitude of vibration due to changes in reed chamber configurations. [Work partially supported by United States National Science Foundation Grant PHY-1004860.]
Modulation and instability in the sound of plastic soprano recorders
Authors: Rucz Péter , Angster Judit , Miklós András
Published: June 2017

Soprano recorders are among the most popular wind instruments in music education for children. As these instruments are played by amateurs, they should be easy to play even by beginner players. The investigations reported in this paper were initiated by an instrument maker company. It was found that their plastic soprano recorders often had unsatisfactory sound quality and exhibited hard playability and strange, unstable steady state sounds, especially in the low regime. The experiments reported here were performed in order to examine the characteristic properties of these unusual sounds and to identify the background causes of the observed phenomena. In this contribution the results of various measurements carried out on different plastic soprano recorders are presented. Recorder sounds and edge tones are analyzed in the steady and attack transient states and their key properties are compared. The observed instabilities, strong amplitude modulations and the appearance of subharmonic components in the steady state sound are discussed. Finally, possible physical explanations of the experimental results are examined.
Viscoelastic internal damping finite-difference model for musical instruments physical model sound production
Authors: Bader Rolf
Published: June 2017

A viscoelastic model for the internal damping of musical instrument parts, like membranes or plates is implemented within a Finite-Difference Time Domain (FDTD) method. Internal damping of wood, leather, nylon, mylar, glue, or varnish strongly change the timbre of musical instruments and the precise spectrum of this damping contributes strongly to the individual instrument character. The model assumes a complex, frequency-dependent and linear stiffness in the frequency domain, which is analytically transferred into the time-domain using a Laplace transform. The resulting mass-weighted restoring force integral of the respective membrane or plate differential equation is solved using a circular buffer accumulation method for each spatial node on the geometry, which is effective, as the model is implemented on a massive parallel Graphics Processing Unit (GPU). The model is able to reproduce arbitrarily shaped internal damping frequency responses with sharp bandwidth and fast response. The model is also able to reproduce other energy distribution problems, like energy loss or even energy supply by different parts of musical instruments through coupling, time-dependent energy loss and supply behavior, or nonlinear damping behavior, like amplitude-dependent loss strength. So also internal damping of metamaterials can be calculated with this model.
In-situ estimation of transmission loss based on learned dictionaries and sparse reconstruction
Authors: Botts Jonathan , Ross Mark A. , Summers Jason E. , Gaumond Charles F.
Published: June 2017

Transmission loss is an important and notoriously difficult quantity to estimate in real underwater environments. Used to evaluate detections and threshold exceedances, estimates of transmission loss may be affected by approximate knowledge of weather conditions, bathymetry, bottom properties, and sound-speed profile—among other sources of environmental uncertainty. For applications in multistatic antisubmarine warfare, a relatively small number of in-situ measurements are available. In this work, in-situ measurements of transmission loss are used to reconstruct transmission loss fields using matching pursuit over a learned dictionary of transmission-loss fields for a given operational area. The dictionary is trained on simulated transmission-loss fields with inputs derived from historical data and plausible variations of environmental parameters. A principal challenge is constraining the problem in such a way that fields may be meaningfully reconstructed given a small set of measured data. The feasibility of reconstruction is evaluated for both full-field and depth-independent transmission-loss fields. Plausibility of practical application is evaluated with respect to realistic sampling conditions. [Portions of this material are based upon work supported by the Naval Air Systems Command.]