bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Sound Transmission Class and Outdoor-Indoor Transmission Class for specification of exterior facade assemblies
Authors: LoVerde John , Dong David W.
Published: June 2017

Design and specifications of the acoustical performance of the exterior facade of buildings to protect the occupants from transportation noise sources is a common acoustical task. Single number quantities (SNQ) are useful to specify and communicate acoustical performance to other design professionals. Common SNQ values include Sound Transmission Class (STC) and Outdoor-Indoor Transmission Class (OITC). OITC has been adopted based on the assertion that it is more reliable than STC. This paper will compare the SNQ using a large dataset and evaluate if there is any advantage of using OITC over STC as the method of specifying or communicating exterior facade performance.
Brazilian acoustics regulation: An overview and proposal of façade requirements
Authors: Monteiro Carolina R. , Borin Marcel , Shimote Mariana , Yanagiya Teddy , Machimbarrena María
Published: June 2017

The Brazilian acoustics regulation for new residential buildings entered into force in 2013, and during the past years, the construction and acoustic consultancy market developed new procedures to accomplish with the façade requirements. In this paper, typical existing methods are presented, as well as new proposals to be incorporated in the future revision of the Regulation. Furthermore, existing and possible future Brazilian requirements are translated to the suggested descriptor DnT,50 and compared within the acoustic classification scheme for dwellings proposed in ISO/CD 19488.
Meta-analysis of subjective-objective sound insulation data
Authors: Brunskog Jonas , Rasmussen Birgit
Published: June 2017

A smaller meta-analysis using field data for subjective sound insulation in dwellings is carried out, using and analyzing data found in the literature. The investigated parameter is the correlation coefficient between the sound insulation metrics and the subjective annoyance (or similar). Both airborne and impact sound insulation is considered. One of the objectives are to see if low frequency adaptation terms according to ISO 717 will yield an increased correlation or not. Other investigated aspects is the influence of lightweight versus heavyweight building elements and the question regarding the importance of vertical versus horizontal transmission.
On the definition of acoustic comfort in residential buildings
Authors: Vardaxis Nikolaos - Georgios , Bard Delphine , Persson Waye Kerstin
Published: June 2017

The aim of this study is to explore acoustic comfort in family apartments in Scandinavia, not only regarding standardized acoustic data but also including the users’ perception of their living sound environment. A first approach takes place for the definition of the concept of acoustic comfort, which was rarely defined before and used to be mostly interpreted as absence, low, or acceptable levels of noise in a place. In this article, acoustic comfort is not only lack of discomfort, it is explained as the ability to have proper sound conditions in overall, for a certain activity in a certain space, considering physical characteristics and the users' demands. Then, a method is set up for the evaluation of comfort in dwellings, including acoustic measurements and social surveys in test buildings. A questionnaire for the collection of the subjective responses of the tenants, regarding noise annoyance, sound perception, and emotions, is presented and analyzed.
Vocal effort of teachers in different classrooms
Authors: Balint Jamilla , Ludwig Rafael P. , Graber Gerhard
Published: June 2017

Classroom acoustics can be one of the reasons for causing voice disorders among teachers. The purpose of this study was to investigate the vocal effort of teachers and the noise level of students under different classroom conditions (reverberant and less reverberant classrooms, junior and senior level, different teaching types like teacher-centered teaching and team work). We were able to carry out measurements over a period of two weeks, where the same two classes were taught by the same teachers in a reverberant classroom during the first week and in a less reverberant classroom during the second week. The results indicate a much greater increase in the vocal effort of the teachers over a period of 6 hours in a reverberant classroom compared to a less reverberant classroom. In addition, teaching younger students requires a greater vocal effort since the noise level is much higher. Also, extended breaks are crucial for the recovery of the voice in reverberant spaces, whereas the voice needs less time to recover in less reverberant spaces. A questionnaire filled out by the participating teachers confirmed that the level of exhaustion at the end of the day is much greater in reverberant spaces.
Shipboard echosounders negatively affect acoustic detection rates of beaked whales
Authors: Cholewiak Danielle , Izzi DeAngelis Annamaria , Corkeron Peter , Van Parijs Sofie M.
Published: June 2017

Beaked whales are cryptic, deep-diving odontocetes that are sensitive to anthropogenic noise. While their behavioral responses to navy sonar have been the subject of extensive study, little effort has been expended to evaluate their responses to other types of acoustic signals, such as fisheries echosounders. From 1 July to 10 August 2013, the Northeast Fisheries Science Center conducted a shipboard cetacean assessment survey, combining visual observation and passive acoustic data collection. Simrad EK60 echosounders were used to collect prey field data; echosounder use was alternated on/off on a daily basis to test for an effect on beaked whale detection rates. The software package Pamguard was used to detect, classify, and localize individual beaked whales. A GLM was used to test the relationship between acoustic detections and covariates; echosounder use negatively affected beaked whale acoustic detection rates, and acoustic event durations were significantly shorter. These results suggest that beaked whales are reacting to echosounders by either moving away or interrupting foraging activity. This decrease in detectability has implications for management and mitigation activities. The use of scientific echosounders is rapidly increasing, thus leading to potentially broad ecological implications for disturbance effects on these sensitive species as well.
Signature whistles facilitate reunions and/or advertise identity in Bottlenose Dolphins
Authors: Macfarlane Nicholas , Janik Vincent , Jensen Frants H. , McHugh Katherine , Sayigh Laela , Wells Randall , Tyack Peter L.
Published: June 2017

Animals with stable relationships need mechanisms to stay in touch when separated. Five decades of research suggest that signature whistles are likely candidates for serving this contact-calling purpose in bottlenose dolphins. However, difficulties identifying the vocalizing individual and measuring inter-animal distances have hindered tests of call functions among wild dolphins. Moreover, signature whistles almost certainly serve a variety of functions, so that to focus on contact calling, it is useful to identify contexts where animals need to maintain cohesion. By simultaneously tagging pairs of mothers and calves to look at instances when the animals are separating and reuniting, we focus on testing specific contact functions of signature whistles. Drawing from the literature, we define three potential contact call functions for signature whistles, each with its own hypothetical signature whistle distribution during separations and reunions: location monitoring, reunion calls, and identity advertisement calls. To test these potential functions, we estimated the probability of an animal producing a signature whistle at different stages of temporary separation events. Using a binomial logistic regression model, we found that the data are consistent with signature whistles functioning as reunion calls or identity advertisement calls but not for location monitoring during separations and reunions.
Submesoscale dynamics in the coastal ocean
Authors: Baschek Burkard , Benavides Ingrid , North Ryan P. , Smith Geoffrey , Miller Dave
Published: June 2017

High-resolution observations reveal the fast dynamics of submesoscale eddies in the coastal ocean. The eddies seem to play an important role in the ocean energy cascade and are thought to be important drivers for phytoplankton production. The eddies are frequently observed in the coastal and open ocean and are characterized by sharp gradients of 1°C/m and high Rossby numbers >10. In order to simultaneously resolve the short temporal and spatial scales of submesoscale eddies, an observational multi-platform approach with planes, a zeppelin, several vessels, gliders, and floats was used yielding a horizontal and vertical resolution of <1 m with repeat observations every 1 to 15 min. The Submesoscale Experiments (SubEx) took place off Catalina Island, CA, and off Bornholm in the Baltic Sea. Observations were carried out with aerial sea surface temperature and hyperspectral measurements, rapid in situ measurements with a towed instrument array, gliders with turbulence probes, as well as surface and subsurface velocity measurements with drifters, as well as Radar and Acoustic Doppler Current Profilers. Additional SAR, SST, and ocean color satellite imagery is used to investigate the occurrence of submesoscale eddies in the coastal ocean. The observations indicate intense mixing, turbulent dissipation, and subsequent restratification. The temperature distribution is closely linked to phytoplankton concentrations suggesting a strong bio-physical coupling.
Recent development and application of inverted echo sounders in observational physical oceanography
Authors: Li Qiang , Farmer David , Duda Timothy F. , Ramp Steven R. , Mao Xianzhong , Park Jae-Hun , Zhu Xiao-Hua
Published: June 2017

Since the first experiment carried out by Rossby in Bermuda, inverted echo sounders have been used in physical oceanography observations for half a century. The inverted echo sounder measures the round-trip acoustic travel time from the sea floor to the sea surface, thus acquiring vertically integrated information on the thermal structure, from which the first baroclinic mode of thermocline motion can be inferred. Arrays of inverted echo sounders have been deployed almost all over the global ocean to observe internal waves, mesoscale eddies, western boundary currents, etc., providing valuable targeted data for physical oceanographers. Acoustic aspects of the inverted echo sounder performance have been recently examined. Sources of error affecting instrument performance include tidal effects, barotropic adjustment, ambient acoustic noise and sea surface roughness. The latter two effects are explored with a simulation that includes surface wave reconstruction, acoustic scattering based on the Kirchhoff approximation, wind generated noise, sound propagation, and the instrument's signal processing circuitry. Not only does the analysis enhance our understanding of the acoustic travel time data but also suggests new approaches to extend the application of inverted echo sounders, for example, for sensing wind over the sea. New deployments of inverted echo sounders and recent developments in hardware system and auxiliary accessories are also introduced.
Susy, Seascan, and other acoustical contraptions
Authors: Trevorrow Mark V.
Published: June 2017

In the early 1990s, the acoustical oceanography research group, led by Dr. David Farmer, developed several high-frequency sonar platforms for near-surface oceanography. These platforms, suspended approximately 25 m below the surface, typically supported six frequencies of upward-looking echo-sounders and up to four steerable 100 kHz sidescan sonars. Additionally, the SUSY platform had four extensible arms, 4.5 m in length, each supporting a wideband hydrophone. The platforms had sufficient batteries and data recording for up to 40 hours of autonomous operation, which could be extended through scheduled on/off periods. The intent of these platforms was to investigate properties of near-surface bubble due to breaking waves, with additional Doppler velocity measurements of surface waves and convective circulations. These platforms were also used for other studies, such as tidal convergence zones and ship wakes. The SEACAN platform was also used to assess zooplankton and fish populations in lake in Japan. This presentation will review key field trials and scientific achievements generated through use of these platforms.
Effects of soft tissue inhomogeneities on nonlinear propagation and shock formation in high intensity focused ultrasound beams
Authors: Yuldashev Petr V. , Bobina Anastasia S. , Khokhlova Tatiana D. , Maxwell Adam D. , Kreider Wayne , Schade George R. , Sapozhnikov Oleg , Khokhlova Vera
Published: June 2017

Recent pre-clinical studies on boiling histotripsy (BH) of kidney in vivo have shown that the presence of soft tissue inhomogeneities such as skin, fat, and muscle layers do not prevent shock formation required for treatment. However, the increase in source power required to compensate for tissue aberrations may be impractically high and result in nearfield damage. Simulations can provide deeper insight into the impact of aberrations on shock formation in tissue and mitigation methods. A previously developed numerical solver of the Westervelt equation was refined to account for tissue inhomogeneities assuming that backward scattering effects can be neglected. Irradiation of human kidney using a single-element 1-MHz transducer with 5-cm radius and 9-cm focal distance was considered. Spatial distributions of the sound speed and mass density in tissue were reconstructed directly from a 3D CT scan. Values of nonlinear and absorption coefficients at each spatial location were assigned by CT image segmentation, using known literature data for different tissue types. Results are illustrated and discussed, including degradation of the focal maximum, shock formation, power compensation requirements, and the potential for modeling the impact of inhomogeneities through the use of an elevated equivalent attenuation. [Work supported by RSF-14-12-00974 and NIH R01EB7643.]
Atlas-based simulations of high-intensity focused ultrasound
Authors: Treeby Bradley , Jaros Jiri
Published: June 2017

In silico investigations of high-intensity focused ultrasound (HIFU) have many applications, including patient selection (determining whether a patient is a good candidate for therapy), treatment verification (determining the cause of adverse events or therapy failures), and treatment planning (determining the optimum sonication parameters before therapy). Here, we use a patient atlas to study the effects of tissue heterogeneities on HIFU sonications in the kidney and liver. The patient atlas is derived from a segmentation of digital cryosection images from the Visible Human Project run by the U.S. National Library of Medicine. For each organ, simulations were repeated under both linear and nonlinear conditions, for different driving frequencies, and for several artificial configurations. These included using a constant sound speed, constant impedance, no absorption, and without particular anatomical features (e.g., the muscle, skin, and ribs). The relative importance of absorption, reflection, refraction, nonlinearity, and frequency is described. The parallel computing requirements needed to perform these large-scale full-wave ultrasound simulations in heterogeneous and absorbing media are also discussed.
Nonlinear ultrasound simulations using the discontinuous Galerkin method
Authors: Kelly James F. , Zhao Xiaofeng , McGough Robert J.
Published: June 2017

Histotripsy with nonlinear ultrasound is an emerging noninvasive therapeutic modality that generates cavitation with high-intensity shock waves to precisely destroy diseased soft tissue. Numerical simulation of these shock waves in nonlinear, absorbing media is needed to characterize histotripsy systems and optimize treatments. We are developing a discontinuous Galerkin code based on the Westervelt equation to simulate transient wave propagation in the brain and skull. The discontinuous Galerkin method is a good choice for this simulation problem since this approach has high-order accuracy, geometric flexibility, low dispersion error, and excellent scalability on massively parallel machines. The Westervelt equation is formulated in a first-order flux form and discretized using a strong form of the discontinuous Galerkin method. Numerical results, both linear and nonlinear, from 1D and 2D discontinuous Galerkin codes, are presented and compared to both analytical and numerical benchmark solutions. In particular, the discontinuous Galerkin method captures nonlinear steepening of a high-intensity pulse with minimal numerical artifacts. The development of a 3D massively parallel code is also briefly discussed. [This work was supported in part by a grant from the Focused Ultrasound Foundation.]
Focusing ultrasound through bones: Past, current, and future transcostal and transskull strategies
Authors: Aubry Jean-Francois
Published: June 2017

Bones reflect, refract, distort, and absorb ultrasonic waves. Most medical application of ultrasound avoid bony structures. Nevertheless, for liver and brain therapy, the rib cage and the skull are in the ultrasonic path. We will present non-invasive methods to detect the presence of the ribs and shape the beam in order to sonicate in between the ribs. It is thus possible to non-invasively aim a target shadowed by the rib cage while avoiding sonication through the bones. Such approaches take advantage of the ultrasonic imaging capabilities of multi-element arrays. Nevertheless, non-invasive brain therapy requires to sonicate through the skull. CT and MR- based techniques have been developed to estimate the phase shifts induced by the skull. Dedicated multi-element arrays have been developed to generate the appropriate phase-corrected signals. The number of elements of the arrays has progressively increased in order to shape at best the corrected beam (64 elements in 2000, 300 in 2003, and 1024 in 2012): clinical transcranial therapies will be presented for the treatment of essential tremor, parkinsonian tremors, and tumors with a 1024 element array. We will also present preliminary results of a novel game changing transcranial focusing technique requiring a dramatically lower number of elements.
Flash focus ultrasonic images sequences for shear shock wave observation in the brain
Authors: Espindola David , Pinton Gianmarco
Published: June 2017

Nonlinear shear waves have a cubic nonlinearity which results in the generation of a unique characteristic odd harmonic signature. This behavior was first observed in a homogeneous gelatin phantom using ultrafast plane wave ultrasound imaging and a correlation-based tracking algorithm to determine particle motion. However, in heterogeneous tissue, like brain, the heterogeneities generate clutter that degrades motion tracking to the point where the shock waves and their characteristic odd harmonics are no longer observable. We present a high frame-rate ultrasound imaging sequence consisting of multiple focused emissions that improves the image quality and reduces clutter to generate high quality motion estimates of shear shock waves propagating in the brain. A point spread function analysis is used to characterize the improvements of the proposed imaging sequence. It is shown that the flash focus sequence reduces the side lobes by 20 dB while retaining the same spatial resolution translating to a sensitivity up to the 11th harmonic. The flash focus sequence are then used to acquire high frame-rate (6500 fps) ultrasound movies of an ex-vivo porcine brain in which a shear wave propagates. Using an adaptive tracking algorithm, we compute the particle velocity in a field of view as deep as the brain. It is therefore demonstrated that the proposed method can detect the nonlinear elastic motion and the odd harmonics with sufficient sensitivity to observe the development of a shear wave into a shock wave as it propagates in the brain.
Sub-millimeter bistatic passive acoustic mapping
Authors: Elbes Delphine , Paverd Catherine , Cleveland Robin , Coussios Constantin
Published: June 2017

Passive acoustic mapping (PAM) is an emerging technique used to image sources of non-linear acoustic emissions, such as inertially cavitating bubbles, during ultrasound therapy. When using a conventional diagnostic ultrasound array, the transverse resolution is typically an order of magnitude better than the axial resolution, which may be inadequate for monitoring treatment at acoustically large distances from the array. Here, we describe an experimental technique that utilizes two orthogonal and coplanar 128-element linear arrays (6.25 MHz centre frequency) to overcome this limitation. The resolution of bistatic PAM was quantified by varying the distance between sources, as well as the array-to-sources distance. The optimal number of elements required was identified by considering the resolution, the accuracy in quantifying the energy of acoustic emissions, and the computational cost. The resulting resolution (achieved with 256 elements) was close to theoretical transverse resolution limit, on the order of hundreds of microns, and the advantage of bistatic PAM over conventional monostatic PAM was illustrated in the context of non-invasive fractionation of the intervertebral disc. It is concluded that, at depth, bistatic PAM enables improved real-time treatment monitoring on biologically relevant length scales. [Work supported by UK Engineering and Physical Sciences Research Council (EP/K020757/1).]
Characterization of cavitation-radiated acoustic power using single-element detectors
Authors: Rich Kyle T. , Mast T. Douglas
Published: June 2017

Standard approaches to quantifying cavitation activity using emission measurements made by single-element passive cavitation detectors (PCD) would be facilitated by improved quantitative and system-independent characterization techniques. Although the strength of an individual emission source can be determined from absolute pressure measurements by a calibrated PCD, this approach requires spatially resolved detection of single bubbles at known locations. Here, a method is shown for characterizing an ensemble of emission sources, quantified by their radiated acoustic power per unit area or volume of a defined region of interest (ROI). An analytic diffraction-correction factor relating frequency-dependent PCD-measured pressures to cavitation-radiated acoustic power is derived using a spatial integral of the PCD sensitivity. This approach can be applied to measurements made by any PCD without a priori knowledge of the number or spatiotemporal distribution of cavitation bubbles. Simulations show that cavitation-radiated acoustic power per unit ROI volume or area is accurately recovered by compensation of emissions received by focused or unfocused PCDs. Measurements from previous sonophoresis experiments are analyzed, showing that skin permeability changes from 0.41 or 2.0 MHz sonication are comparably correlated to the radiated acoustic power of subharmonic emissions per unit area.
Cylindrically converging nonlinear shear waves
Authors: Cormack John M. , Spratt Kyle S. , Hamilton Mark F.
Published: June 2017

The low shear moduli of soft elastic media permit the generation of shear waves with large acoustic Mach numbers that can exhibit waveform distortion and even shock formation over short distances. Waves that converge onto a cylindrical focus experience significant dispersion, causing waveforms at the focus and in the post-focal region to differ significantly from the source waveform even in the absence of nonlinear distortion. A full-wave model for nonlinear shear waves in cylindrical coordinates that accounts for both quadratic and cubic nonlinearity is developed from first principles. For the special case of an infinite cylindrical source with particle motion parallel to the axis, for which nonlinearity is purely cubic, the nonlinear wave equation is solved numerically with a finite-difference scheme. The full-wave model is compared with a piecewise model based on a generalized Burgers equation for cylindrically converging waves outside of the focal region and linear diffraction theory in the focal region. For waveforms with wavelength much smaller than the source radius, conditions are explored for which the approximate piecewise model shows good agreement with the full-wave model. [Work supported by the ARL:UT McKinney Fellowship in Acoustics.]
Design, development, and implementation of low cost high performance mufflers for heavy duty diesel engines
Authors: Rao Mohan D.
Published: June 2017

In this paper, details on the design and fabrication of affordable high-performing passive exhaust mufflers and associated low volume manufacturing technology for commercial heavy duty diesel engines are presented. The exhaust noise radiation to the atmosphere from large diesel engines used in earth-moving, military, and other heavy equipment machines ranks as a major noise source of the urban environment. A solution to this problem is the use of mufflers to significantly reduce noise pollution to the atmosphere. There are several types of common mufflers, including reactive designs using resonators, expansion chambers, perforations, and dissipative configurations using absorptive materials. The design and realization of mufflers for a particular engine is dependent on several design parameters, such as internal combustion engine characteristics, acoustical requirements by standards, production volumes and cost, with the requirements varying from application to application. Particulars of successful muffler designs for three different machines—a commercial excavator, a tele handler, and a military ground vehicle are presented in this paper. The designs include both box type and round mufflers with Helmholtz resonators, reversible flow chambers, and perforated tubes, all capable of custom fabrication using conventional manufacturing processes in a local machine shop using commercially available materials.
Joe McMaster: “Telling your story and bringing abstract ideas to life on screen.”
Authors: McMaster Joseph
Published: June 2017

Mark Twain said, “I like a good story well told. That is the reason I am sometimes forced to tell them myself.” So how might you tell the story of your scientific research in engaging ways? And what can you do if non-scientists find the subject difficult or hard to visualize? Award winning science journalist and filmmaker Joe McMaster shares concrete examples of what has worked (and sometimes not worked) in his 25 years of making films about science and technology for television and the web—many of which have required bringing abstract ideas to life on screen.
A cross-university massive open online course on communication acoustics
Authors: Möller Sebastian , Ahrens Jens , Altinsoy M. Ercan , Buchschmid Martin , Fels Janina , Hillmann Stefan , Hohnerlein Christoph , Müller Gerhard , Seeber Bernhard U. , Vorlaender Michael , Weinzierl Stefan , Knoth Sebastian , Barodte Wolfram
Published: June 2017

Four of the nine big Technical Universities in Germany, together with Chalmers University of Technology in Sweden, have developed a new Massive Open Online Course (MOOC) on the subject of Communication Acoustics. The idea is to foster education on the late Bachelor or early Master level by joining the expertise available at individual universities and by creating an online course offered both to local as well as remote students. The course started in winter term 2016 and is hosted on the EdX platform. It is offered in English language and roughly divided into two parts: The first part covers basics on acoustics, signal processing, human hearing, speech production, as well as electroacoustics and psychoacoustics. The second part introduces selected applications, such as sound recording and reproduction, sound fields and room acoustics, binaural technology, speech technology, as well as product sound design. The course material consists of explanatory videos and text as well as audiovisual material, exercises, and self-assessments. The final examination takes place as a written or online exam, with physical presence at the contributing sites. The talk will provide insights into the experiences we made, and illustrates how we overcame the obstacles inherent to cross-university education.
K-12 students and Freshmen College Teaching Pattern for Science
Authors: Bhatta Ambika , Nsumei Patrick , Cabanas Rafael
Published: June 2017

This paper presents a model of classroom physics instructions at Health & Human Service (HHS) high school, Lawrence, Massachusetts. Our focus is to create new approaches, procedures, and concepts used in our classrooms to reach the demography. The challenge is to motivate them to do and appreciate science, particularly physics and acoustics. The presented work utilizes the model of audio, video, computer aided and theoretical modalities to help students’ access to the fundamental concepts. It will also be shown that it complements any inefficiency in Math and high order thinking skills.
Conceptual understanding and situational interest of middle-school-aged youth who participate in 4-day soundscape science camp
Authors: Ghadiri Khanaposhtani Maryam , Liu ChangChia James , Pijanowski Bryan C. , Shepardson Daniel
Published: June 2017

The purpose of this study was to investigate how participation in an inquiry-based environmental camp contributed to the conceptual understanding and triggered the situational interest of middle school-aged youth to a new field called “Soundscape Ecology.” The focus of this study was to understand how participants were affected cognitively and affectively by primary attributes of the immersive soundscape activities. We used descriptive interpretive approaches and several sources of data from drawing activities, pre-post questionnaires, interviews, observations, and participant artifacts. Our study showed that participants’ conceptual understanding as well as their interest were positively affected by variables such as direct interaction with nature, access to authentic technology, collaborative teamwork, and having choice and control. Our results suggest that scientific field work, combined with opportunities to engage youth in scientific education through the use of authentic tools, has the potential to foster an environment in which participants can better comprehend scientific principles.
David Wessel—The IRCAM years
Authors: Machover Tod
Published: June 2017

David Wessel was a musical visionary who combined scientific rigor, technological savvy, and sonic adventure to powerfully influential the formative years of Pierre Boulez’s IRCAM in Paris. Wessel was trained in mathematics and percussion, receiving a Stanford Ph.D. in musical psychoacoustics. He brought these specialties to computer music at the crucial moment when real-time digital synthesis was being developed. His Antony (1977) was the first musical work to use Giuseppe di Giugno’s 4A machine, and his Timbre Maps (1978) demonstrated for the first time that sonority alone could produce structural relationships. Wessel brought free-jazz principles to live computer music performance, and was a pioneer in understanding and influencing the development of MIDI. Wessel became IRCAM’s Director of Pedagogy in 1980, and in that role inspired a generation of international composers, technologists and scientists, a veritable Who’s Who of today’s most prominent creators. As a member of IRCAM’s Artistic Committee, Wessel influenced the selection of artists for IRCAM residences and helped to invent a successful model for combining pedagogy, research and creation. Above all, David Wessel’s omnivorous love of all kinds of music, and his deep generosity, brought an unequaled spark of humanity to the world of man, music, and machines.
A methodology to awake citizens' awareness on the effects of leisure noise
Authors: Maffei Luigi , Masullo Massimiliano , Ciaburro Giuseppe , D'Onofrio Luigi
Published: June 2017

In recent years, several cities’ administrations have proposed projects of urban renewal of historical districts to face state of neglect and degradation problems. Frequently these projects include new outdoor social activities such as pubs, bistros, and shops along and/or on the streets with a huge amount of investments, and the success of these projects is then measured through the increase in local population and tourists that frequent, during day and night time, these sites. On the other hand, more people frequent these sites more crowd noise and more consequent complaints of the resident population can be expected. Finally, the due imposition of administrative restrictions can nullify the original aim of the project. Starting from these considerations, a methodology based on sound recordings of different outdoor gathering spaces, on subjective questionnaires administered during listening tests, on features extraction's algorithms, and finally on the artificial neural networks is proposed. The methodology aims to improve the awareness of citizens about the impacts that leisure noise may have on a specific urban project and in general on the quality of the urban environments.
Nestled in nature and near to noise—The Ford Amphitheatre
Authors: Hoover K. Anthony
Published: June 2017

The historic Ford Amphitheatre was relocated in 1920, from what would later become the location of the Hollywood Bowl, across the Hollywood Freeway, into an arroyo with a dramatic natural backdrop. Since then, the freeway has become increasingly noisy. The original wood structure was destroyed by a brush fire in 1929, and rebuilt in concrete in 1931, with several subsequent modifications and renovations. The current major renovation to this 1200-seat outdoor amphitheatre includes an expanded “sound wall” that will help to mitigate freeway noise while providing optimal lighting and control positions. The remarkably uniform distribution of ambient noise throughout the seating area and the apparent contributions by the surrounding arroyo will be discussed, along with some of the unique design and construction opportunities.
Recovering historic noise
Authors: Jordan Pamela
Published: June 2017

It is easy to think of noise like refuse—an undesired byproduct of other activities to be minimized or eliminated. However, the richest source of information about a historic site is frequently the garbage that individuals and groups have left behind. Applying the same logic, non-designed sound can also be perceived as an essential component of a heritage location, providing a sensorial understanding of past realities as well as contemporary conditions. Could noise be approached as a resource rather than simply a dilemma, even in cities? This paper seeks to reframe the concept of noise in urban environments with a focus on outdoor heritage sites. The Berlin Wall will be presented as a case study where visitors’ perception of unintentional sound provides key information about the past. Inadvertent preservation of historic noise sources and patterns along the Wall, such as vehicular traffic, landscape maintenance, and visitor crowds, has enabled visitors to experience the soundscape of the past in situ rather than through a recording or secondary source. By extending valuations beyond the present moment, it is possible to see the potential value in all sounds.
Soundscape analysis and modeling of outdoor gathering spaces
Authors: Siebein Gary W. , Paek Hyun , Roa Marylin , Siebein Gary , Siebein Keely
Published: June 2017

Case studies of three outdoor gathering spaces will be presented to illustrate the soundscape concepts embodied in each. Case study 1 is an outdoor amphitheater that is located near a residential neighborhood. Concerts at the amphitheater raised concerns from residents about acoustical measuring methods. Case study 2 is a lively restaurant with a large outdoor seating area where guests eat and listen to music played by a single performer or small group. Case study 3 is a series of outdoor restaurants that do not have live entertainment. The use of different types of soundwalks to capture the acoustical signature of these venues; the acoustical communities involved in each situation; taxonomies of the sounds that occur at each; the specific acoustical events that comprise the ambient sound in each case; acoustical measurements and modeling used in the analysis of each venue; the extent of the acoustical rooms for performing and listening; an acoustical calendar; the design of the acoustical interventions; and live experiments to document ranges of conditions to residents are documented and discussed.
Subjective study on attributes related to Mach-cutoff sonic booms
Authors: Ortega Nicholas D. , Vigeant Michelle C. , Sparrow Victor
Published: June 2017

Mach cut-off occurs under certain flight conditions (aircraft speed, atmospheric conditions, etc.) in which sonic booms do not reach the ground’s surface. The theory has been around for over 40 years, but no studies have investigated the perception of such sounds. The goal of the present investigation is to develop a vocabulary related to the perception of these sounds, with the intent on using this vocabulary to study annoyance. The current study uses sounds recorded by NASA’s “Far-field Investigation of No-boom Thresholds” (FaINT) tests. Subjects listened to sets of Mach cut-off audio recordings and were asked to provide descriptors to characterize the sounds. Subjects then listened to each recording and assigned descriptors from their individual set of attributes to each sound, effectively categorizing the sounds. The analysis was performed across subjects to refine definitions and identify commonalities. The vocabulary is used in a follow-up study wherein participants rate their annoyance to a variety of Mach cut-off sounds. The subject test data and subsequent analyses are discussed. [Work supported by the FAA. The opinions, findings, conclusions, and recommendations expressed in this material are those of the authors and do not necessarily reflect the views of ASCENT FAA Center of Excellence sponsor organizations.]
Laboratory test bed for sonic boom propagation
Authors: Bailey Michael , Kreider Wayne , Dunmire Barbrina , Khokhlova Vera A. , Sapozhnikov Oleg A. , Simon Julianna C. , Sparrow Victor W.
Published: June 2017

Varying ethanol concentration with depth, Hobaek et al. [AIP Proc. 838, 2006)] simulated the atmospheric sound speed profile scaled in a water tank and mimicked sonic boom propagation. Some limitations of their groundbreaking design included complexity, fragility, size, safety, one-dimensionality, tonal bursts instead of impulsive shocks, and the inability to scale density, absorption, turbulence, or other nonlinearities. Recognizing the time and cost savings of scaled overflight experiments in a laboratory environment, this work is meant to address certain limitations and investigate the Mach cut-off phenomena. Our primary advances are to use gel layers instead of fluid mixtures and lithotripter shock pulses. We defocused and modified a Dornier Compact S lithotripter to vary source angle in a 500-liter polycarbonate tank, measured shocks with a fiber optic hydrophone, and developed fluid-like gels with negligible shear-wave generation and robustness against cavitation. The sound speed, attenuation, inhomogeneity, and nonlinearity are adjustable within each gel layer. The result is a more flexible, controllable, and durable atmospheric analogue. [Work supported by the FAA. The opinions, findings, conclusions, and recommendations expressed in this material are those of the authors and do not necessarily reflect the views of ASCENT FAA Center of Excellence sponsor organizations.]
Numerical simulation of sonic boom focusing and its application to mission performance
Authors: Rallabhandi Sriram , Fenbert James W.
Published: June 2017

This paper describes the effort undertaken to include numerical boom focusing on a lossy Burgers equation based sonic boom propagation tool called sBOOM. Traditional ray acoustics may break down during acceleration or other aircraft maneuvers that cause the ray tube area to approach zero. The paper describes a way to numerically predict focused sonic boom signatures using both Gill-Seebass similitude and the solution to the non-linear Tricomi equation that models the physics of boom focusing. The paper would then use this capability to determine focusing and non-focusing climb trajectories and their impact on mission performance.
International Civil Aviation Organization Supersonic Task Group overview and status
Authors: Liu Sandy R. , Tong Bao
Published: June 2017

A resurgence of interest in supersonic flight has emerged due to recent technological advances. Given the global impact of such aircraft, environmental standards and recommended practices (SARP) are being developed under the International Civil Aviation Organization (ICAO) to ensure the mitigation of accompanying sonic booms prior to any re-introduction of civil supersonic flight operations. In 2004, ICAO’s Committee of Environmental Protection (CAEP) established the supersonics work program under Working Group 1 (WG1) to develop SARPs. Current proposed concepts include (1) traditional sonic boom aircraft (like the Concorde), which operate supersonically over water; (2) low-boom designs with overland operation capabilities; and (3) traditional aircraft flying under Mach cut-off conditions. To-date, WG1/SSTG continues to formulate an enroute sonic boom SARP for civil supersonic airplanes. Metrics, test procedures, and a data framework continue to be investigated for suitability and efficiency. A newly formed Landing and Take-Off (LTO) noise subgroup for supersonic aircraft has been tasked to define a second SARP for the terminal environment (i.e., subsonic operations). An overview of ICAO’s hierarchy supporting SARPs development, WG1/SSTG technical program, and a current status update is presented.
Infrasound and low frequency sound emitted from tornados
Authors: Talmadge Carrick L.
Published: June 2017

The NCPA, in collaboration Hyperion Technology Group, has performed a series of measurements of infrasound and low-frequency sound generated by tornadic thunderstorms near Oklahoma City, OK, during a large-scale outbreak on May 24, 2011. Ground truth for tornado tracks as well as meteorological data were available for these storms. Infrasound and low-frequency sound were identified separately for a long duration EF-5, an EF-4, and an EF-2 tornado. As reported by Frazier et al. [JASA 135, 1742 (2014)], infrasound in two distinct regions were noted: An infrasound band between approximately 1-10 Hz and a low-frequency audible band located between roughly 40-200 Hz (center frequency around 80-100 Hz). As part of the NOAA VORTEX-SE initiative, the NCPA will be collecting additional infrasound data in the Northern portion of Alabama, centered on Huntsville and the Sand Mountain region. Current plans are to install to 10 infrasound arrays, with seven elements per array. As part of the same VORTEX-SE initiative, seven additional arrays will be deployed by the University of Alabama Huntsville. We will report here on the status of infrasound generated by tornadic thunderstorms, as well as discuss the status of modeling efforts to understand the origins of these emissions.
Wind noise reduction using a compact infrasound sensor array and a Kalman filter based on the Matérn Covariance Function
Authors: Frazier William G.
Published: June 2017

A method for real-time estimation of stationary infrasound signals such as microbaroms in wind noise at low signal-to-noise ratios using a compact infrasound sensor array is presented. A compact array is defined as a sensor array that has an aperture that is much smaller than the shortest infrasound wavelengths of interest and is unsuitable for estimation of direction-of-arrival. In this application, the spacing between sensors results in the measured wind noise being highly correlated, and therefore, simple averaging cannot be used to obtain a good estimate of the infrasound signal. However, by adequately modeling the spatiotemporal wind noise process, array gain can be realized. The method is based on using a Kalman Filter that is designed with the assumption that the measured wind noise can be adequately modeled as a dynamic Gaussian random field with a Matérn covariance function (demonstrated previously at the ASA Meeting in Salt Lake City, Utah, May, 2016). The presentation describes how to design the Kalman Filter in order to estimate the infrasound signal of interest, demonstrates the filter performance using synthetic and measured data from a compact array, and describes how to extend the method to support changing wind conditions and non-stationary infrasound signals.
Active diffracting gratings for vortex beam generation in air
Authors: Muelas H. Ruben D. , Pazos-Ospina Jhon F. , Ealo Joao L.
Published: June 2017

Vortex beams VB have gained great attention because of their interesting features, e.g., autorreconstruction ability, capacity to transport and transfer angular momentum, among others. Different applications have been proposed, e.g., particle manipulation and rotation control of particles/objects. Recently, VB generated in water using passive structures have been reported. In particular, multi-arm spiral slits are used attached to a radiating source. In this work, we propose a new alternative to generate VB in air. Specifically, we use active diffracting gratings easily fabricated by gluing a ferroelectret film on a lower electrode, structured on a PCB, that perfectly resembles the desired geometry. The active material is not cut to size and shape. See [1]. Consequently, a transducer with the geometry of the intended grating radiates the acoustic energy. Broadband spiral active gratings are employed to create VB in air at frequencies between 100 and 200 kHz. Numerical simulations are compared with experimental results. This new class of transducers paves the way to the creation of complex radiation fields in a rapid, cheap, and efficient manner. [1] J. Ealo, J. Camacho, and C. Fritsch, “Airborne ultrasonic phased arrays using ferroelectrets: a new fabrication approach,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control 56(4), 848-858 (2009).
Electro-oculography based horizontal gaze tracking: A perspective for attention-driven hearing aids
Authors: Hladek Lubos , Brimijoin W. Owen , Porr Bernd
Published: June 2017

Users of hearing aids with standard directional microphones can have difficulties in complex listening situations such as multi-talker environments because they must turn their heads to follow conversations that move rapidly from one talker to the next. The use of gaze-pointed hearing aid directionality has been suggested as a way to potentially alleviate this problem [Kidd et al. (2013); J. Acoust. Soc. Am. 2013; 133(3): EL202-7.] However, to arrive at a practical and usable device, there is the need for unobstructive and mobile technology for gaze tracking. Here, we propose and evaluate an algorithm for estimating eye-gaze angle based solely on the single channel electro-oculogram (EOG), which can be obtained directly from the ear canal using conductive hearing aid molds. In contrast to conventional techniques, we use an algorithm which calculates the absolute eye angle by statistical analysis of the saccades. This results in robust long term performance where predicted eye angles significantly correlate with actual eye angles. This opens up the possibility of an attention driven beam-former for hearing aids without the need for eye-tracking goggles. [This work was supported by the Medical Research Council [grant number U135097131], Chief Scientist Office (Scotland) and Oticon Foundation.]