bluuebunny/crossref_metadata_2025 huggingface dataset:
Sonority of adjacent segments in the perception of durational distinctions
Authors: Dmitrieva Olga
Published: May 2014

The distributional typology of length contrasts in consonants suggests that the sonority of adjacent segments may be relevant for the perception of duration differences in consonants. Across languages, short consonants typically contrast with long consonants intervocalically or next to high sonority consonants, such as glides or liquids. It has been proposed that surrounding sonorants facilitate the perception of durational distinctions by providing clear acoustic cues to the beginning and the end of the target consonant, which makes it easier to estimate the target's duration (Bradley, 2001; Padgett, 2003). The present study investigates this hypothesis by examining the effect of adjacent segments' sonority on the perception of durational differences in alveolar voiceless stops. Target stops of two lengths were placed in the environment of a preceding or following vowel, liquid, nasal, fricative, or non-homorganic stop and presented to listeners in a discrimination experiment. Initial results indicate an important role for syllable structure and its sonority profile in duration discrimination: Listeners appear to be more sensitive to length distinctions when stops targets are in the onset position preceded by a higher-sonority coda (e.g., al.ta) compared to stop targets in the coda position followed by a higher-sonority onset (e.g., at.la).
Defining spectral and temporal resolutions of information-bearing acoustic changes for understanding noise-vocoded sentences
Authors: Stilp Christian , Goupell Matthew
Published: May 2014

Information-bearing acoustic changes (IBACs) in the speech signal are highly important for speech perception. This has been demonstrated for full-spectrum sentences using cochlea-scaled entropy (CSE; Stilp and Kluender, 2010 PNAS) and noise-vocoded sentences using an adapted metric (CSECI; Stilp et al., 2013 JASA). While IBACs appear fundamental to speech perception most broadly, Stilp et al. tested a single set of vocoder parameters, obscuring the breadth and depth of perceptual reliance upon these acoustic changes. Here, TIMIT sentences were noise-vocoded with variable spectral resolution (4-24 spectral channels spanning 300–5000 Hz), variable temporal resolution (4–64 Hz amplitude envelope cutoff frequency), or combinations therein. High-CSECI or low-CSECI sentence intervals were replaced with speech-shaped noise. As spectral resolution decreased, IBACs became more important for sentence understanding, especially at 6–12 channels. At high spectral resolutions, performance nearly overcame replacement of low-CSECI intervals but not high-CSECI intervals. Importance of IBACs at different temporal resolutions was largely driven by overall intelligibility, suggesting CSECI has sufficient temporal resolution at low modulation frequencies. Data exploring spectral-temporal tradeoffs will also be presented. Peak-picking strategies in CIs select and stimulate channels according to their amplitudes, but results suggest additional perceptual benefit may be offered by encoding IBACs as well.
Model-based underwater signal processing—The Carey factor
Authors: Candy James V. , Sullivan Edmund J.
Published: May 2014

The sustained encouragement and belief in the model-based approach to underwater processing has always been one of the favorite topics of Bill Carey's conversation. Not only by his direct encouragement, but also his contributions in the form of well-executed, well-controlled and well-documented experiments in the Hudson Canyon area off of the New Jersey coast that has become known as the best and most complete sets of oceanic data available for signal processors to apply their latest algorithms. It has become affectionately known as the “canonical” oceanic signal generator and often stated by many signal processors that “if your algorithm is not capable of performing well on the Carey Hudson Canyon data, then it is not worthy of pursuing it further.” His experimental work is a major contribution to the underwater processing area. In this paper, we briefly discuss the Hudson Canyon data set and show the performance of a model-based processor that was applied to localize a source using a 23-element hydrophone array in shallow water.
Measuring seismic waves using a towed underwater acoustic array
Authors: Collis Jon M. , Pierce Allan D.
Published: May 2014

This paper discusses the possibility of detecting shear and interface (Scholte) wave effects in the ocean using a towed hydrophone array. The shear field will be evanescent in the water and so may only be detected near to the ocean bottom interface. A benefit of measuring the acoustic field with a towed array is that a Hankel transform can be used to construct the horizontal wavenumber spectrum. If a shear or interface wave is measured, then it will be visible in the horizontal spectrum. The possibility of detecting the shear field will be strongly dependent on the shear wave speed in the sediment and this will also affect the detection of the more difficult to detect Scholte wave, which travels at about 90 % the shear wave velocity. The Scholte wave has a circular polarization where the shear wave may be vertical, horizontal, or a combination of the two polarities and may not be detectable for all frequency and source depth configurations. [Work supported by ONR.]
Bill Carey and the development of our understanding of ocean acoustic coherence
Authors: Colosi John A.
Published: May 2014

One of the many topics for which Bill Carey had an enormous passion was coherence. Unlike many researchers who elect to stay in either the observational or theoretical sides, Bill jumped into both areas with zeal, uncovering important navy data and working with the theorists of the day. This talk will summarize some of Bill's most seminal work in the area of coherence, and the talk will demonstrate how Bill's ideas live on in recent developments on the subject.
Using narrowly defined hypotheses to extract meaningful results from broad data sets
Authors: Pfeiffer Scott D.
Published: May 2014

Data sets come in many forms, from modeled or calculated results, to in-situ measures, to bodies of work that provide collected sets of evidence. The collective data set can often be overwhelming, and can provide conflicting results, or present a level of uncertainty in analysis. Narrowly defining the questions to ask of the data based on the strengths and weaknesses of each tool seemingly enables discovery of the needle(s) in the haystack. Listening experiences in live settings provide the hypotheses that steer the analysis utilizing all of the tools at our disposal. Experience with targeted analysis of very specific phenomena are discussed from recent projects.
Evaluation of acoustic diversity of religious buildings; case study from churches and mosques in Turkey
Authors: Kocyigit Filiz B. , Akbaş Gamze , Ozal Gokhan , Yerli Can , Gunduvan Meral , Demirer Feyyaz
Published: May 2014

In this study, by analyzing the reverberation time and noise insulation features of religious structures, effects of differences on the forms, materials, and functions on interior acoustics are discussed. For this purpose, calculations were made working on the projects of the selected sample mosques and churches built by different materials and their interior reverberation times were measured and compared. Two different types of areas were compared using RT60 reverberation time calculations and T30 and T20 frequency band analysis measurement systems. In the comparison, interior functions are evaluated. In this evaluation, it was observed that in mosques since there is excessive speaking, medium frequency resulting from people was more dense whereas in churches high frequency was also involved with rite taking place alongside the medium frequency resulting from talking. Therefore, interior frequency band width was observed to increase. Selected churches have cross and basilic type plan and mosques have square type plan. It is observed that selected traditional mosque roofs have circular forms and churches have sharp forms. Hereby variations of the acoustic features of the sites with different forms and functions used for similar purposes were compared.
Evaluating methods of acoustic analysis in a small listening room
Authors: Levins Jennifer
Published: May 2014

Although common, octave band analysis of decay times provides limited information on the behavior of sound in a room. In spaces for critical listening, additional analysis is required in the design phase. Even in existing spaces, measurements of reverberation time do not always reveal room anomalies such as echoes and standing waves. The acoustic experience of the space is not always indicated by reverberation time. In rooms for critical listening, additional methodologies such as modal analysis, ray tracing, and early reflection times are used to determine additional information about a room's acoustic characteristics. A case study will be presented to demonstrate the applicability of these methods in small listening rooms.
Experimental verification of computer modeled loudspeaker sound level performance based on excitation signal
Authors: Woolworth David S. , Naderyan Vahid
Published: May 2014

An investigation of a loudspeaker sound level performance in a simple geometry to verify the EASE sound level definition comparing pink noise and multi-tone signal utilizing field tests of loudspeakers.
Efficient computational modeling of Platonic solid loudspeaker directivities
Authors: Mortensen Jeshua H. , Leishman Timothy W.
Published: May 2014

Dodecahedron loudspeakers are commonly used in architectural acoustics measurements as quasi-omnidirectional sources of sound. Other Platonic solid loudspeakers may also be used for this purpose, but the geometrical properties that optimize their omnidirectional behaviors are not well understood. Because of the difficulties in constructing large numbers of loudspeakers and boundary element models for related investigations, a computational method has been developed for the MATLAB environment to rapidly predict radiated fields and observe general directivity trends as geometrical properties vary. The method is based on related spherical enclosure geometries. It enables one to easily assess the effects of altered driver diameters, positions, numbers, vibrational patterns, and enclosure volumes. This presentation discusses the tool and presents several computational findings. Its output is presented as animated frequency-dependent balloon plots and area-weighted spatial standard deviations. The results are found to agree well with similar predictions for actual Platonic solid geometries from the boundary element method and experimental measurements.
A two-point method for direct measurement of the room constant
Authors: Jensen Zachary R. , Leishman Timothy W.
Published: May 2014

The room constant is a key frequency-dependent value that is widely used to characterize reverberant fields. It is typically estimated from room boundary properties, viz., total surface area and average absorption coefficient. Unfortunately, these properties are often difficult to ascertain with sufficient accuracy. While reverberation times may be adequately measured using modern methods, the effective surface areas and volumes of many practical rooms are elusive. Furthermore, several formulations for the room constant exist without general agreement as to their best usage. This presentation introduces a two-point energy-based method that enables acousticians to feasibly measure the room constant without knowledge of the room volume, surface area, or average absorption coefficient. Numerical simulations and measurements illustrate the benefits of the approach. Resulting values are compared with those approximated using common formulations for validation and clarification.
Variation in the acoustic behavior of right whale mother-calf pairs
Authors: Parks Susan , Conger Lisa , Cusano Dana , Van Parijs Sofie
Published: May 2014

North Atlantic right whale mother-calf pairs are a critical segment of the population for recovery of this endangered species and therefore their protection is paramount. Passive acoustics, including the development of real-time buoys, has increasingly played a role in the detection of right whale presence in high vessel traffic areas. The vocal behavior of North Atlantic right whale mothers and their young calves has not been well described and may not be well represented by calls produced by other individuals in the population that are commonly utilized for passive acoustic monitoring. Therefore, it is critical to determine the call types and rates of sound production by mother-calf pairs to assess the efficacy of passive acoustic monitoring for their detection. We conducted behavioral focal follows coupled with acoustic recording of right whale mother calf pairs off the coast of Florida and Georgia in January–March, Cape Cod Bay in April, and the Bay of Fundy in August–September from 2011 to 2014. Results show modifications in both call structure and call rate with increasing calf maturity and independence. These data are necessary to better utilize passive acoustic monitoring for management purposes in this species.
Long-term acoustic surveying of bats
Authors: Surlykke Annemarie , Andreassen Tórur , Hallam John
Published: May 2014

Increasing concern about decline in biodiversity has created a demand for population surveys. Long-term unmanned automatic monitoring may provide unique unbiased data from a whole season, but the large amount of data presents serious challenges for automatic processing. A two-month study of echolocating bats at 500 kHz sampling rate provided 236 GiB of data at full bandwidth. We used a Support Vector Machine (SVM) classier based on a combination of temporal and spectral analyses to classify events into bat calls and non-bat events. Duration, energy, bandwidth, and entropy were used to identify bat calls and reject short noise pulses, e.g., from rain. The SVM classifier reduced our dataset to 162 MiB of candidate bat calls with an estimated accuracy of 96% for dry nights and 70% when it was raining. The automatic survey revealed correlation between bat activity and rain, temperature, and sunset/sunrise. There were calls from two species new to the area, as well as an unexpected abundance of social calls. Future applications aim at higher accuracy in classifying bat calls and using trajectory-tracking to determine flight paths to correct for the bias toward loud bats inherent in acoustic surveying.
Construction of a new underwater low-frequency projector based on clarinet acoustics
Authors: Acquaviva Andrew A.
Published: May 2014

Understanding theoretical models of novel designs is a crucial component of developing early prototypes. This presentation discusses a new underwater low-frequency sound source. This system is based on a model of a clarinet-like source that is designed to work underwater, such that the complete assembly incorporates all of the necessary components required for a real clarinet to produce sound. The resulting device can, with proper set up and understanding of clarinet acoustics, produce a stable tone at significant amplitudes. Furthermore, the harmonic content substantiates the validity of the model on which it is based.
Design of piezo-micro-electro-mechanical systems for low frequency energy harvesting
Authors: Shamkuwar Swapnil D. , Dekate Kunal N.
Published: May 2014

The exibility associated with piezoelectric materials makes them very attractive for power harvesting. Piezoelectric materials possess a large amount of mechanical energy that can be converted into electrical energy, and they can withstand large strain magnitude. The critical physical dimensions of MEMS devices can vary from well below one micron on the lower end of the dimensional spectrum, all the way to several millimeters. While the functional elements of MEMS are miniaturized structures, sensors, actuators, and microelectronics, the most notable (and perhaps most interesting) elements are the microsensors and microactuators. Microsensors and microactuators are appropriately categorized as “transducers,” which are defined as devices that convert energy from one form to another. In the case of microsensors, the device typically converts a measured mechanical signal into an electrical signal. Mechanical compression or tension on a poled piezoelectric ceramic element changes the dipole moment, creating a voltage. Compression along the direction of polarization, or tension perpendicular to the direction of polarization, generates voltage of the same polarity as the polling voltage. Hence, by changing device physics, we may get a sensor with higher output with low power consumption and reduced size of the device. The proposed piezoelectric sensor will be designed in COMSOL software and respective characteristics analysis will be observed.
Room acoustics and pipe organs: Putting a STOP to common misunderstandings
Authors: Shade Neil T.
Published: May 2014

Misunderstandings about room acoustics exist among architects, building committees, musicians, organ consultants, and organ builders. These range from opinions with no acoustic validity to simple confusion of acoustic principles by those not versed in our science. Common and repeated mistakes this author has encountered while serving as an acoustic consultant to numerous worship houses are discussed along with a rational basis to correct such unfounded beliefs.
The Musical Instrument Digital Interface (MIDI): The digital organ for organists and non-organists
Authors: Wheeler Paul
Published: May 2014

The Musical Instrument Digital Interface (MIDI) is a technical protocol (standardized in 1983) to connect a wide variety of electronic musical instruments. Digital organs, due to increased sound quality and lower pricing, have become a popular alternative to pipe organs. They also provide an advantage of controllability through MIDI. Using MIDI, digital organs can be connected to a variety of sound modules, greatly increasing the number of stops available for organists. For the non-organist composer, organ music can be written in notation software (such as Finale) and played on an actual digital organ. The challenge in writing music for playback through MIDI is to incorporate organ techniques (such as shortening of repeated notes, legato playing by finger crossing or finger substitution, and finger glissandos) so that the result does not sound like a pianist (or a computer) playing the organ. A MIDI capable digital organ can be advantageous for organists and non-organists alike.
Apparatus for demonstrating evanescent waves in acoustic waveguides
Authors: Russell Daniel A. , Ludwigsen Daniel O.
Published: May 2014

A physical demonstration apparatus, inspired by [K. Meykens, et. al., Am. J. Phys., 67(5), 400–406 (1999)] is used to demonstrate evanescent sound waves in a rectangular waveguide. The apparatus consists of a rectangular waveguide, approximately one meter in length, with one optically transparent wall. The waveguide is driven at one end by a pair of loudspeakers whose polarity may be switched. The other end of the waveguide is open. The sound field inside the waveguide may be interrogated using a microphone and an oscilloscope. The apparatus will be used to demonstrate several features of acoustic wave guides, including the propagation of plane waves, the cutoff frequency for non-plane waves, the propagation of non-plane waves above the cutoff frequency, and the exponential decay of evanescent non-plane waves below the cutoff frequency. The educational and teaching applications of this apparatus will be discussed.
Demonstration of an extremely directional acoustic source
Authors: Wilson Preston S. , Dolder Craig N. , Hamilton Mark F.
Published: May 2014

Highly directional light sources such as flashlights and lasers are well known to most people. In contrast, highly directional acoustic sources, or in other words, sources of sound that are audible in only a very narrow region of space, are far less common. Many people have never experienced such a source, and the phenomenon is not found in nature. A highly directional source of sound known as a parametric array is used underwater for sonar applications, but the frequency (pitch) of the sound is often above the human hearing range. Similarly, highly directional, focused sound sources are regularly used in medical applications, but again, the frequency is too high to be heard. The narrowness of the acoustic beam cannot be experienced by human listeners. Recently, parametric array technology has been commercialized for use in air at frequencies in the human auditory range. These devices produce extremely narrow (on the order of 2 degrees) beams of audible sound. When pointed directly at one listener, the sound is virtually inaudible to another listener only a few feet away. Such a device will be demonstrated and the basic physics behind its operation will be explained.
Constantine Trahiotis and hearing science: A half-century of contributions and collaborations
Authors: Bernstein Leslie R.
Published: May 2014

Although best known for his contributions to human binaural processing, Constantine (Tino) Trahiotis has, throughout his career, been an avid student of virtually all aspects of hearing. His published work spans nearly 50 years and has been carried out with an impressive cadre of collaborators worldwide (all of whom he thinks of as family). That body of work attests to the diversity of Tino's interests and encompasses behavioral and lesion studies in animals, human psychoacoustics, mathematical modeling, methodology, signal-processing, and instrumentation. Tino's recall of the literature is legendary. As compared to the use of traditional methods to locate publications concerning a particular topic, many of us, especially the string of scientists he has mentored, know that it is often more efficient to just pick up the phone and ask Tino. This presentation traces the history of Tino's career, including his days as a graduate student with Don Elliott at Wayne State University, his time at Indiana University, and as a Professor at the University of Illinois and at the University of Connecticut Health Center.
Tino Trahiotis's impact on general binaural research progress
Authors: Colburn H. Steven
Published: May 2014

The evolution of thinking and understanding in binaural hearing research over the past six or seven decades will be reviewed. Both physiological and psychophysical developments, as well as their interactions and applications, will be described. The focus of this review will be the impactful role that Tino Trahiotis played across this wide spectrum of research areas. Tino's large impact came through his personal engagement with the ideas and the people involved in this research. His enthusiasm for the topic is contagious and provides fuel for digging deeper and making connections across diverse research topics. The progress has been exciting and the whole process has been great fun... consistent with the Trahiotis style. [Work supported by NIH/NIDCD DC00100.]
Nonlinear behavior of heterogeneous materials containing snapping acoustic metamaterial inclusions
Authors: Konarski Stephanie G. , Spratt Kyle S. , Haberman Michael R. , Hamilton Mark F.
Published: May 2014

This work studies the forced dynamical behavior of a heterogeneous material containing metamaterial inclusions undergoing large deformations. The inclusions exhibit non-monotonic stress-strain behavior, modeled with an expansion to third order in volume strain, where the coefficients of the expansion depend on the metamaterial structure. The resulting constitutive behavior of interest displays regimes of both positive and negative stiffness and the inclusion therefore exhibits hysteretic snapping when forced by an acoustic pressure. Two cases are explored using a generalized Rayleigh-Plesset analysis to model the large-deformation dynamics of the metamaterial inclusion following an approach similar to Emelianov et al. [J. Acoust. Soc. Am., 115, 581 (2004)]. The first case focuses on the forced dynamics of a single inclusion embedded in a weakly compressible elastic medium. The second case broadens the model to analyze the behavior of a heterogeneous material comprised of a low volume fraction of non-interacting metamaterial inclusions embedded in a weakly compressible material. Finally, estimates of the effective bulk modulus and loss factor of the heterogeneous medium are presented for instances of the forcing pressure inducing either large or small inclusion deformation. [Work supported by the ARL:UT McKinney Fellowship in Acoustics and the Office of Naval Research.]
Large-amplitude stress waves in nonlinear periodic structures
Authors: Wang Pai , Casadei Filippo , Bertoldi Katia
Published: May 2014

The ultimate goal of this research is to investigate the propagation of large-amplitude stress waves in nonlinear periodic structures. Sources of non-linearity are associated with large-strain kinematics, material non-linearity, and bifurcation paths. In this study, we use a numerical approach to investigate the propagation on large strain waves in periodic lattice structures of finite size. Insights on the dispersion properties of such systems, and their functional dependence on the strain levels, are obtained by post-processing the time-history results obtained through time-domain explicit simulations. In particular, we highlight the effects of nonlinear amplitude parameters on the bandgaps and wave directionality of the considered systems.
Arrays and signal processing during the “Nantucket Sound Experiment”: A review of work in honor of William M. Carey
Authors: Holmes Jason D.
Published: May 2014

Bill Carey was an engineer at heart and he loved finding practical solutions to important sonar problems. The development of a small hydrophone array towed by an unmanned vehicle built off of practical experience in one area of Bill's expertise (towed array signal processing and coherence length) and served as a practical tool to investigate another area he was interested in (acoustics of bottom interaction). This paper discusses what Bill referred to as the “Nantucket Sound Experiment” in which the small towed array was deployed. The development of the array, its use to measure sediment properties by forming a long synthetic aperture, and the relationship between synthetic array performance and coherence are discussed. Particular attention is paid to Bill's insight into the mechanisms that influenced array performance for various aspects of the experiment.
Bill Carey as a scientist, motivator, sponsor, and colleague
Authors: Muir Thomas G. , Knobles D. P. , Penrod Clark
Published: May 2014

Bill Carey's long association with the Applied Research Laboratories at the University of Texas at Austin (ARL:UT), gave us the pleasure and good fortune to be associated with him in a wide range of pursuits, over many years. His insight and fortitude as a scientist and motivator led a number of us into productive scientific research that we may not have otherwise undertaken. As a sponsor at the Defense Advanced Research Projects Agency (DARPA), he posed visceral questions with unique viewpoints, sometimes in forceful terms, which led us to undertake difficult and productive projects. Some of these projects are linked to the series of shallow water sea trials called the Area Characterization Tests, which proposed and tested hypotheses, while collecting invaluable data to delineate the acoustics of significant scenarios in littoral ocean environments. We were privileged to participate in these experiments as well as analyze and model the results. As a colleague, while at other institutions, Bill provided the motivation and encouragement for us to undertake many projects, including a seismo-acoustic experiment with the SACLANT Undersea Research Center, which demonstrated the dispersive beam-forming concept for geophone arrays on the sea floor and for the detection and study of Sholte type interface waves. We pay tribute to Bill Carey in this talk by illustrating some of the discoveries made in a number of at-sea experiments and the theoretical and modeling work they spawned. [Work supported by ARL:UT Austin.]
Chris Jaffe's contributions to the Concert Hall Research Group
Authors: Foulkes Timothy
Published: May 2014

One of Chris Jaffe's many contributions to acoustics was his involvement in the Concert Hall Research Group (CHRG). In 1992, Chris had the idea of sending three measurement teams to the same concert halls for the dual purpose of getting current data and also to see how close the results would be between different teams measuring the same hall. From the inception of the CHRG in 1992 until a few months before his death in 2012, Chris was a source of ideas, inspiration, and energy.
Fortuitous coupling: A recollection of how Chris Jaffe brought together coupled rooms and Texas oil money to launch a graduate program and a career
Authors: Summers Jason E.
Published: May 2014

Early in his career Chris Jaffe discovered that reverberation-starved Vaudeville theaters could be improved through use of light-weight demountable shells for the stage enclosures. These shells could be designed for frequency-dependent “selective transmission” of energy into the otherwise unused stage house, realizing a “fortuitous coupling” that improved acoustics for the audience and on-stage musicians. My experience with Chris at Rensselaer Polytechnic Institute (RPI) is also one of fortuitous coupling, as he orchestrated the launch a new graduate program in architectural acoustics. Chris had just overseen the completion of Bass Performance Hall in Fort Worth, Texas, which realized the culmination of his design philosophy for stage-house coupling in multipurpose theaters. Now, Bass Hall was to become a laboratory for studying the science underlying Chris's empirical findings. RPI, Chris's alma mater, was to be the institutional home for that research. And Ed Bass, scion of the Bass family and primary benefactor of the hall's construction, would provide the initial support. As a student, about to complete my Master's degree and ready leave physics for audio engineering, a chance elective course followed by a Medici-esque offer to study the physics of coupled rooms radically shifted the course of my professional life.
A subtraction technique for removing playback noise from high-frequency rodent recordings
Authors: Abbasi Mustafa Z. , Pasch Bret , Humber Amilia , Ryan Michael J. , Wilson Preston S.
Published: May 2014

The efficacy of animal communication often necessitates signalers to adjust signals. For example, many vertebrates modify vocal output to minimize interference from ambient noise (e.g., Lombard effect) or in response to other signaling animals. Such auditory-feedback-mediated vocal control is well documented in songbirds, humans, and nonhuman primates, but has not been explored in rodents. Alston's singing mouse (Scotinomys teguina) emit advertisement vocalizations that function in mate attraction and male-male aggression, and can vary both temporal and spectral features depending on the social context. In this experiment, we investigated the extent to which mice can modify vocal output in response to perturbations in auditory feedback by broadcasting conspecific vocalizations that overlapped a focal male's song. However, an unexpected challenge was found in separating the mouse's vocalization from the broadcast stimuli. Other studies have used Golay codes to measure the impulse response of the system and subtract the noise. However, such techniques could not be applied herein due to the high frequencies produced by mice; movement of the mouses' head appears to change the system sufficiently to prevent effective subtraction. The authors will present a novel method using spectral envelopes and cross-correlation procedures to garner feedback on the validity of this technique.
Twists and turns, in cochlear anatomy: Curvatures related to infra vs ultrasonic hearing
Authors: Ketten Darlene R. , Simmons James , Riquimaroux Hiroshi , Cramer Scott , Arruda Julie
Published: May 2014

Microchiropteran bats and odontocete cetaceans are sophisticated echolocators with acute ultrasonic hearing operating in radically different media. Similarly, elephants and mysticetes share the ability to generate and respond to infrasonics. In this study, the heads, outer, middle, and inner ears of 32 specimens from 11 species of bats, dolphins, elephants, and whales were analyzed with microCT (11 to 100 micron isotropic voxel imaging; Siemens Volume Zoom and X-Tek CT units). Canal length, basilar membrane dimensions, and cochlear curvatures varied widely among all species. Length correlates with body mass, not hearing ranges. High and low frequency limits correlate with basilar membrane ratios and radii ratios, which are a measure of the radius of curvature. The ears of the known echolocators were significantly different from the mid to low frequency ears, with increased stiffness, thicker membranes, and outer osseous laminae supporting up to 60% of the basilar membrane. Anatomical correlates of “foveal” regions with stretched representation for peak echolocation spectra were found in both bat and porpoise ears. Radii and membrane ratios are consistent despite media and are predictive of high and low frequency hearing limits in all ear types. [Work supported by NIH, JIP, N45/LMRS -US Navy Environmental Division, and ONR Global.]
Numerical simulation of sound generation by Cicada
Authors: Hughes Derke , Pierce Allan D. , Katz Richard A. , Koch Robert M.
Published: May 2014

The principal anatomical structures in the cicada that radiate sound are two platelets referred to as tymbals, which vibrate after being struck by ribs that have undergone buckling. This research effort investigates the sound of these ribbed finite plates connected to a parallel surface by a nonlinear spring. When individual ribs are placed under compression, the linearized version of the model predicts eventual exponential growth of the transverse displacement when the compressional load exceeds the buckling load. The nonlinear spring, however, stops this growth and a subsequent oscillation ensues. The actual anatomy of the cicada is more complicated than this basic model. However, this simplified mathematical explanation is given as a means to describe sound emitted in a sequence of closely spaced tone bursts. The energy from these sound impulses are stored in tensed muscles and released via buckling into the kinetic energy of ribs, which is similar to striking a drum. The tymbals “ring” at a frequency controlled by the mass of the tymbals and the air cavity “spring” within the abdomen. This ringing vibration affects the amplitude, cycles within each pulse, and the damping of the tymbal function to generate the efficiency of the cicada sound radiation.
Using high-frequency ultrasound to detect cytoskeletal dysfunction in Alzheimer's disease
Authors: Calder Ashley N. , Sugiyama Janice E. , Thompson Laurel A. , Doyle Timothy E.
Published: May 2014

Recent work indicates that Alzheimer's disease (AD) affects the cytoskeleton and cellular structure through mutations that alter structural proteins, and that dysfunction of the cytoskeleton may play a pivotal role in AD and other neurodegenerative diseases. The goal of our research is to determine if high-frequency ultrasound can detect cytoskeletal dysfunction in AD. Research on the molecular subtypes of breast cancer indicate that mutations specific to each subtype may change the characteristics of the cytoskeleton and resulting properties of the cell such as size, shape, and stiffness. Both computer simulation and experiment have demonstrated that high-frequency ultrasound in the 10–100 MHz range is sensitive to these properties. For this study, ultrasonic tests were conducted on monolayer cell cultures of breast cancer cell lines of different subtypes. The ultrasonic spectra were compared and correlated to model results using a pattern recognition algorithm. Preliminary results indicate that cell stiffness and size can be determined from the measurements. The cytoskeletal properties of the cells were additionally modified by chemical and physical agents such as the introduction of colchicine and electric fields to mimic the effects of AD. Results from these and future studies with neuron cell cultures will be discussed.
Noise pollution in the 21st century
Authors: Blomberg Leslie D.
Published: May 2014

What will 21st century noise be and sound like? Will this century be noisier than the 20th century? What changes to noise policy and noise control are we likely? This paper explores these questions. The historical context of the last 100 years will be used to examine and understand the possibilities for the next 100 years.
Non-invasive methods for diagnosing diseases of the ear: Wideband acoustic immittance and umbo velocity
Authors: Merchant Gabrielle R. , Rosowski John J. , Nakajima Hideko H.
Published: May 2014

Measurements of ossicular motion using laser Doppler vibrometry (LDV) in patients with various ear diseases, along with fresh cadaveric experiments, have increased our understanding of how sound is transduced to the cochlea and how this transduction is modified by various conductive pathologies. These studies have dispelled some misguided beliefs, changed clinical treatments, and shown the potential of LDV as a diagnostic. LDV, however, has substantial limitations as a clinical tool. For patients with conductive hearing loss of unknown etiology (where general otologic exam and conventional tympanometry are not diagnostic), another non-invasive measurement, wideband acoustic immittance (WAI, directly related to power reflectance), in conjunction with audiometric measurements, can differentiate between ossicular fixation, ossicular discontinuity and superior canal dehiscence (SCD). Furthermore, WAI measurements show a common pattern in power reflectance in patients with SCD, with or without a conductive hearing loss. An algorithm to identify this pattern in power reflectance suggests that WAI may be a simple, inexpensive screening tool for SCD. Evidence will be presented from our studies on patients with various otologic diseases, as well as from fresh cadaveric preparations simulating various diseases. Power reflectance can assist in treatment decisions and prevent unnecessary and inappropriate treatments and surgeries.
Murray Strasberg, a role model
Authors: Blackstock David T.
Published: May 2014

Murray Strasberg held several different offices in the Acoustical Society: Executive Council Member 1969–1972, President 1974–1975, and Secretary 1987–1990. The Society was very fortunate to have Murray at its helm in 1974–1975. Wallace Waterfall died early in Murray's term. ASA old timers remember Wallace as the man who “ran the Acoustical Society out of his hip pocket” for years and years. How were we going to get along without him? Murray led us painstakingly through the difficult reorganization. Also up was the Standards issue. ASA decided to write and publish its own acoustical standards rather than leave them to other organizations. Finally, the recent birth of INCE had sadly led to turf wars, which had to be dealt with. Several years later, long after most presidents have happily gone out to pasture, Murray again stepped up, in this case to fill the void caused by Betty Goodfriend's retirement as ASA Secretary. Murray served as ASA's last Secretary. Beyond his splendid service to the Acoustical Society, Murray was a renowned acoustical scientist and, perhaps above all, a warm and generous friend.
Differences in the human response to freight and passenger railway vibration in residential environments
Authors: Sharp Calum , Woodcock James , Peris Eulalia , Moorhouse Andrew , Waddington David
Published: May 2014

The aim of this paper is to quantify and investigate differences in the human response to freight and passenger railway environmental vibration. Data for this research comes from a field study comprising interviews with respondents and measurements of their vibration exposure (N = 752). A logistic regression model has been developed to classify measured railway vibration signals in the field study as freight or passenger signals, with a classification accuracy of 96%. Exposure-response relationships for annoyance due to exposure to freight and passenger railway vibration are then determined using an ordinal probit model with fixed thresholds. These exposure response relationships indicate that the annoyance response for exposure to freight railway vibration is significantly higher than that for passenger railway vibration. In terms of a community tolerance level, the population studied is 15 dB (re 10−6 m s−2) more tolerant to passenger railway vibration than freight railway vibration. The potential reasons for this difference in the human response are investigated and discussed. Some of the factors that are investigated include time of day effects, sleep disturbance, effects of combined noise and vibration and the effects of social, attitudinal, and demographic factors.
Acoustic measures of falsetto voice
Authors: Keating Patricia
Published: May 2014

Falsetto (or loft) voice is known to be generally characterized by a high fundamental frequency, a spectrum with relatively few harmonics, and a relatively strong fundamental harmonic. The present study tests the hypotheses that falsetto voice differs from modal voice not only in the acoustic measure H1*-H2* (the amplitude difference between the first and second harmonics, corrected for formant frequencies and bandwidths), but also (1) in H2*-H4* (the amplitude difference between the second and fourth harmonics, corrected for formant frequencies and bandwidths), and (2) in spectral noise as measured by harmonics-to-noise measures. These and other acoustic measures will be obtained for selected pairs of vowels using VoiceSauce, the UCLA program for voice analysis. The test corpus comprises pairs of sentences taken from two readings of the story “Little Red Riding Hood” by 17 speakers of American English (8 women, 9 men). Each speaker read the story first in a neutral voice, and then using character voices for the dialogs, which for these 17 speakers were often in falsetto. The goal of the study is a reliable acoustic measure of falsetto voice.
Utilizing an extended target for high frequency multi-beam sonar intensity calibration
Authors: Heaton John L. , Weber Thomas , Rice Glen , Lurton Xavier
Published: May 2014

There is an interest in expediting intensity calibration procedures for Multi-Beam Echo-Sounders (MBES) to be used for acoustic backscatter measurements. To this end, a target was constructed of irregularly oriented small chain links arranged in a “curtain” simulating an extended scattering surface, such as the seafloor. Tests with a 200-kHz, 7°, SIMRAD EK60 Split-Beam Echo-Sounder (SBES) were performed in a tank in order to investigate the targets angular- and range-dependent scattering strength. These tests suggest that the amplitude envelope of the scattered signal is Rayleigh distributed and that the backscatter strength depends linearly on the number of active scattering elements. Following these initial validation tests, a 200 kHz Reson SeaBat 7125-SV2 MBES was calibrated in the tank with the same extended target. During the calibration, the MBES was rotated so that every beam was incident on the target. This calibration test was performed once when the target was at normal and once at oblique (45°) incidence. The final output is a “catch all” beam-dependent calibration coefficient, C, determined from the sonar equation.
Broadband modeling of sound propagation in shallow water with an irregular elastic bottom
Authors: Li Li , Piao Shengchun , Zhang Haigang , Mo Yaxiao , Tang Jun
Published: May 2014

The purpose of this work is to study the propagation of broadband sound pulses in shallow water environments. It is essential for an underwater pulse propagation model to handle bottom interaction, range-dependence, and wide-angle propagation in shallow water. Therefore, a comparatively realistic model that consists of a fluid overlying an irregular elastic bottom is treated, where the effects of shear wave are included. The range-dependent seismo-acoustics problem in frequency-domain is solved by a parabolic equation model. Fourier synthesis of frequency-domain solutions is implemented to model the received time series of a broadband sound propagation. And parallel programming is tried to improve the computational efficiency. Dispersion characteristics are exhibited by multiple mode arrivals during the propagation, including the dispersion of normal modes and mode 0 (the Scholte wave). The dispersion analysis of normal modes and the Scholte wave are demonstrated under different types of elastic bottoms. Energy converting between trapped modes and leaky modes due to slope of bottom is also analyzed.
The instantaneous frequency variance feature of underwater bottom target
Authors: Li Xiukun , Xia Zhi
Published: May 2014

The key of underwater target recognition is extracting stable target feature from the complicated mixed signal. Deal with LFM pulse, the time-frequency character of target echo is fixed and linear; however, the time-frequency feature of target echo is sensitive with the SRR, the angle of incidence wave, and the shape and the material of target. Based on the geometric acoustic scattering character of a classical bottom target model, the time-frequency distribution of target echo is treated as a bidimensional image in this paper. During with image rotation, the time-frequency distribution of target echo is transformed to a line spectrum, and then, the instantaneous frequency variance feature is extracted. The experiment data processing result has shown that the clusters of target echo and reverberation on this feature are stable for various environments and the shape and the material of targets. The method proposed in this paper is meaningful for construct a universal feature space in the detection of underwater bottom target.
An error reduction method for double-plane nearfield acoustic holography based on boundary element method
Authors: Shang Dejiang , Liu Yongwei
Published: May 2014

Nearfield planar acoustic holography method based on BEM is often used in experiments because it is very convenient to scan the sound field on planes. However, the sound field reconstruction error on the sound source surface is usually very big due to the dimension limitation of measuring planes. The method proposed here, by measuring some extra far field points out of the planes, which are combined with those on the planes to reconstruct the sound field on the source surface, can reduce this sort of error. The numerical simulation has been carried out by this method for a spherical sound source with radius of 1.0 m. The double planes are located at x=±0.6 m, assumed that the sound source is at (0,0,0) in Cartesian coordinate. The max reconstructing error of sound pressure on the sound source surface can be reduced from 6 dB to less than 2 dB at frequency 500 Hz when we add two extra far field points at (0,±10 m,0). Obviously, this method is very meaningful in practical experimental tests. More numerical simulation by this method for more complex sound source field reconstruction will be shown in the full paper.