bluuebunny/crossref_metadata_2025 huggingface dataset:
A preview of the second edition of the AISC Design Guide 11 “Vibrations of Steel Framed Structural Systems due to Human Activity”
Authors: Ungar Eric E.
Published: October 2015

The Steel Design Guide 11, “Floor Vibrations due to Human Activity,” which originally was published in 1997, has been refurbished, updated, and broadened. At the time of the writing of this abstract, a draft is being reviewed by its sponsor, the American Institute of Steel Construction. Like the original, the second edition presents easily used means for predicting the vibrations of floors of steel construction due to typical walking and for assessing the acceptability of these vibrations in relation to human comfort. The new edition relies on more recent data on footfall forces and includes prediction methods (analytically derived and empirically adjusted on the basis of comparison with experimental data) for evaluating the acceptability of walking-induced vibrations on equipment and facilities whose limits are expressed in terms of a variety of measures. Analyses of stairs and pedestrian bridges are included, and modeling of structures with steel joists is discussed. An extensive chapter is devoted to the application of finite-element analysis to floor structures.
The relationship of vibration and groundborne/structureborne noise in buildings relative to vibration in the ground from exterior sources
Authors: Phillips James E.
Published: October 2015

Ground vibration generated by roadway traffic, rail, and transit systems can be transmitted into buildings were it can either be perceived as feelable vibration or as sound radiated from the interior building surfaces, i.e., floors, walls, and ceilings. The amount of vibration that is transmitted into a building is affected by a reduction as the vibration is transmitted from the ground to the foundation of the building (i.e., coupling loss) and amplification due to resonances within the building structure. This paper will discuss these effects and measurements that have been conducted to quantify the effects for common residential building construction adjacent to rail lines. A brief discussion regarding the relationship of groundborne/structureborne noise to interior vibration from exterior sources of ground vibration will be included.
Modeling, designing, and testing low frequency impact isolation solutions for building structures with fitness centers above grade
Authors: Varney Norman D.
Published: October 2015

There is a trend for fitness centers to find a quick, inexpensive occupancy and ideal location in a vacant office or retail space, often above grade. The tenants sharing the building structure are then subjected to sudden airborne noise and structureborne vibration from the impact energy generated by heavy weights being dropped onto the floor. Because of this trend there is a need to analyze the large, low frequency, shock generated energies that travel through the structure. This paper will discuss the process of designing an experimental floor assembly and apparatus to test weight drops, developing a modeling program to simulate weight drops using three degrees of freedom, which can be tailored to varying isolation solutions, and the means of physically testing the results.
Voice disguise and speaker identification
Authors: Didla Grace S. , Hollien Dr. Harry
Published: October 2015

Voice disguise involves deliberately changing one’s voice to conceal their identity. It is most often associated with crimes such as kidnapping, fraud, etc. In addition to being a general problem in the world of crime, it is a particular one in the area of Speaker Identification (SI) and for the following reasons: (1) There appears to be no limit on human ingenuity in the types of disguise that can be employed. (2) While there are unlimited ways to disguise speech, there seem to be far too few studies to provide useful information about it. (3) Further these studies are narrow in scope. This can be attributed to the extensive number of variables (type of disguise, familiarity with the speaker, language, dialect, etc.) and the need for their control. (4) Because of these limitations, a great deal more needs to be known about the major types of disguise and the ones detrimental to SI. Thus, the numerous issues plaguing voice disguise must be addressed systematically through an integrated research program. A review of their nature, the research needed and the reasons for conducting the program will be discussed. Data from a sample experiment of this type will be presented.
Detailing vowel development in infancy using cortical auditory evoked potentials and multidimensional scaling
Authors: McCarthy Kathleen , Skoruppa Katrin , Iverson Paul
Published: October 2015

The present study used an efficient measure of perceptual sensitivity to map perception across the British English vowel space for 80 monolingual English infants (4–5, 8–9, and 10–11 months old). Auditory evoked potentials were measured for spectral changes between concatenated vowels, which, for infants, typically evokes a positivity about 150–200 ms after each spectral change. These were measured for 28 pairs of seven monophthongal vowels (/i/, /ɪ/, /ɛ/, /a/, /ɑ/, /ɔ/, /u/) that were presented in a random concatenated sequence with changes every 300–400 ms. ERPs were averaged across epochs following each spectral change, with the magnitude of the response for each vowel pair used as similarity measure for multidimensional scaling. The 4–5 month old infants had two-dimensional perceptual maps that closely matched the F1 and F2 acoustic differences between vowels. In contrast, the older infant response was less related to acoustic differences and they had selectively larger responses for neighbors around the vowel quadrilateral (e.g., /i/-/ɪ/); suggesting a shift to a more phonologically driven processing. These results provide a more detailed picture of phonetic development than has been shown before, and demonstrate an efficient procedure to map speech processing in infancy.
Brain activity for sound symbolism in visual size judgment: Combinations of voiced and voiceless plosives with a vowel “o” or “i”
Authors: Itagaki Sachi , Murai Shota , Hiryu Shizuko , Kobayasi Kohta I. , Auracher Jan , Riquimaroux Hiroshi
Published: October 2015

Sound symbolism is an idea that sounds itself has the impression. In most of the previous psychology and linguistics researches, stimuli were presented visually with alphabets, and subjects directly answered the impression of the sound. The purpose of this study is that establishing a behavioral paradigm applicable to functional magnetic resonance imaging (fMRI) research when the sound stimulus was presented aurally. In this experiment, we focused on sound symbolism in visual size. Subjects were required to answer visual size difference between standard and target stimulus. Visual stimuli were a gray circle on black background LCD screen. Sound stimuli were /bobo/ and /pipi/, and were assumed to have impression of “bigger” and “smaller,” respectively, according to previous researches. Currently, brain activity of the sound symbolism is examined in MRI using ours previous behavior paradigm. The result suggested that our paradigm is able to use for fMRI study. However, MRI imaging results shows that the location and amount of activity is different by subjects, suggesting the neural substrate of the sound symbolism could vary between individuals. Relationships between the brain differences and individual behavioral differences will be discussed.
How classical ideas inform 21st century architectural acoustics
Authors: Foulkes Timothy , Prokos John
Published: October 2015

This presentation was inspired by John Prokos' essay in Worship Space Acoustics: 3 Decades of Design. It will be a joint presentation by Prokos, an architect and Foulkes, an acoustician. It was Marcus Vitruvius Pollio, the great First Century Roman architect and engineer, who first set forth the famous triumvirate of firmness (structure), commodity (usefulness), and delight (beauty) as the ideals of the architect. Even in today's digital age, these three tenets are as applicable as ever, nowhere more so than in architectural acoustics. This session will consider examples of buildings and spaces whose acoustics are as compelling as their visual design. For firmness, we will look at several examples including Gund Partnership's athletic center at Kenyon College, whose dramatic vaulted glass and steel structure nonetheless allow excellent acoustics. For commodity, among the projects we present is the Young Israel Symagogue in Brookline, MA, a collaboration between the two presenters, which has the flexibility to accommodate varied worship services and gatherings to meet the congregations's changing needs. Among the buildings demonstrating delight is Cavanaugh Tocci's work on the 1100 seat Oratory at Ave Maria University in Florida, a classically inspired church that seeks to replicate the acoustics of the great European cathedrals.
Ocean acoustic tomography: Past, present, and maybe future
Authors: Wunsch Carl
Published: October 2015

This talk will describe some of the origins of what became known as ocean acoustic tomography, and how it has evolved in the intervening years. Some published mis-conceptions about its beginnings are somewhat interesting. The possibilities of its having a more central role in the determining the evolution of the ocean in future climate raise fascinating technical problems that probably have equally fascinating solutions.
Combined lysis of thrombus with ultrasound and systemic tissue plasminogen activator for emergent revascularization in acute ischemic stroke (CLOTBUST-ER): An update
Authors: Alexandrov Andrei V.
Published: October 2015

Background: Continuous exposure of intracranial arterial occlusions to pulsed wave ultrasound enhances tissue plasminogen induced recanalization. Our hypothesis is that sonothrombolysis can improve functional outcomes of stroke patients receiving tPA therapy. Methods: The primary objective is to evaluate the efficacy of a novel transcranial ultrasound device and systemic tPA (Target) compared to systemic tPA alone (Controls) in subjects with acute ischemic stroke and NIHSS scores 10 or greater. This is a randomized (1:1), placebo-controlled, multi-site, phase 3 clinical trial to evaluate the efficacy and safety of a novel ultrasound device, as an adjunctive therapy to tPA treatment in subjects with acute ischemic stroke: total projected enrollment 824 patients with interim analyses at ⅓ and ⅔ of enrollment. Current Status: CLOTBUST-ER had active enrollment at approximately 70 sites in 14 countries worldwide. DSMB recommended to stop the trial after second interim analysis. Functional outcomes are still being assessed via modified Rankin Scores at 90 days and the primary endpoint will be analyzed using ordinal shift statistical analysis. Final results will be presented at ISC 2016. Conclusions: CLOTBUST-ER is the first phase three multinational randomized blinded clinical trial of sonothrombolysis for treatment of acute ischemic stroke. ClinicalTrials.gov Trial Registry ID: NCT01098981.
High throughput acoustic and optical characterization of microbubbles for optimized contrast ultrasound imaging
Authors: Rademeyer Paul , Stride Eleanor
Published: October 2015

Echogenic particles, such as microbubbles and volatile liquid micro-/nanodroplets, have shown considerable potential in a variety of clinical diagnostic and therapeutic applications. The accurate prediction of their response to ultrasound excitation is however extremely challenging, and this has hindered the optimization of techniques such as quantitative ultrasound imaging and targeted drug delivery. Existing characterization techniques, such as ultra-high speed microscopy, provide important insights, but suffer from a number of limitations; most significantly difficulty in obtaining large data sets suitable for statistical analysis and the need to physically constrain the particles, thereby altering their dynamics. Here, a microfluidic system is presented that overcomes these challenges to enable the measurement of single echogenic particle response to ultrasound excitation with a throughput of 20 samples/second and an uncertainty below 7% in the measurements. Demonstration of optimized contrast ultrasound imaging is shown based on the characterization of over 100,000 individual SonoVue® bubbles.
Underwater acoustic calibration facilities at Applied Research Laboratories, The University of Texas at Austin
Authors: Lenhart Richard D. , Wilson Preston S.
Published: October 2015

The calibration of various underwater sources and receivers is routinely undertaken at The University of Texas at Austin’s Applied Research Laboratories using an open water facility, the Lake Travis Test Station, and both indoor and outdoor test tanks on the ARL main campus. Calibrations are also conducted using standing wave facilities and transducer electrical input impedance measurements can be obtained. These facilities and procedures will be described.
Viability of large-scale fit-testing in the U.S. Navy and Marine Corps
Authors: Federman Jeremy
Published: October 2015

In support of the Navy and Marine Corps initiatives to prevent military and civilian personnel from suffering hearing loss due to noise exposure, and to ensure hearing readiness and fitness for duty in the military and civilian workforce, this project explored the potential to implement a fit testing procedure for objectively measuring hearing protection devices (HPDs) performance on individuals. Due to the relative uniformity of noise exposure during recruit training, relevant training and experience, and likelihood of participants having hearing within normal limits, 320 training recruits at USMC MCRD Parris Island were included in Phase 1 and 900 in Phase 2. Factors of interest were fit testing pass-fail rates, test duration, and training. The pass-fail criterion attenuation level was set at 25 dB based on the output level of the M4 weapon used during basic training (Amrein & Letowski, 2012; NIOSH, 2014). Both test duration and PAR estimation accuracy were considered in evaluating the practicality of implementing a fit-testing program. Results of objective fit testing were considered as a metric of training effectiveness and HPD functionality.
Hearing protection fit-test system pilot study: Results and recommendations for the hearing conservation program
Authors: Hecht Quintin , Williams Matthew
Published: October 2015

Since the inception of hearing protection device fit-test systems, long-term training benefits have been scarcely investigated. A hearing protection fit-test system was evaluated for performance and training benefits in a pilot study among U.S. Air Force members randomly sampled from those in the hearing conservation program. Subjects were randomly assigned to control or intervention. Both groups received an initial and a 6-month follow-up appointment. At the initial appointment, the control group received standard training for hearing protection, while the intervention group was fit-tested, trained, and fit-tested again. At the follow-up appointment, both groups received fit-testing. Results of the intervention group’s initial appointment will be examined and the two groups’ follow-up fit-test results will be compared. These findings will be discussed in relation to effects on training and retention. Methods for conducting this study and a descriptive analysis of the subject population will also be reviewed. Recommendations for fit-testing integration into a hearing conservation program will be provided based on our study results and other literature.
Earplug fit testing: Practical examples
Authors: Schulz Theresa Y.
Published: October 2015

Preventing noise-induced hearing loss at the workplace appears deceptively easy. Well-intentioned professionals often assume that providing hearing protectors and administering audiograms are, by themselves, preventive measures. But occupational hearing loss often continues unabated. This presentation shows data from companies that have used best practice techniques to stop noise-induced hearing loss with fit-testing and individual training as their hearing conservation tools. These tools can change the attitudes and behaviors of earplug users, young and old.
A modal analysis view of minimum phase response of acoustic enclosures
Authors: Hashemgeloogerdi Sahar , Bocko Mark F.
Published: October 2015

When the response of an acoustic system is minimum phase, the existence of a stable and causal inverse is assured, which enables compensation for acoustic effects such as reverberation. In this paper, we explore the ranges of minimum phase behavior of one, two, and three-dimensional acoustic enclosures in light of their modal frequency response. We show that a one-dimensional acoustic enclosure, which by definition contains only axial modes, is always minimum phase. The responses of two and three-dimensional acoustic enclosures are characterized by a combination of normal modes in multiple dimensions. We show that two and three-dimensional acoustic enclosures demonstrate minimum phase behavior over limited frequency intervals. Minimum phase response tends to be confined to low frequencies, and a cutoff frequency below which the enclosure is minimum phase is identified.
Sound-induced flash illusion revisited
Authors: Kito Aya C. , Furuyama Takafumi , Kobayasi Kohta I. , Hiryu Shizuko , Riquimaroux Hiroshi
Published: October 2015

Auditory-visual illusion occurs when visual information and auditory information integrates in the brain. This is conceived because auditory information has temporal superiority than visual information. Purpose of the study is to investigate mutuality influence of auditory information and visual information. Subjects answered the number of sounds and flashes when the auditory and visual stimuli are presented. We selected five auditory and visual stimuli (percentage answered as 2 times were 0%, 25%, 50%, 75%, and 100%) from the auditory only and visual only case and combined the stimuli. Subjects answered the number of sounds and flashes when the stimuli are presented simultaneously. When comparing the rate of unilateral and bilateral case, auditory only case and a combination of ambiguous auditory stimuli and definite visual stimuli, auditory information tends to shift toward visual information. This result suggests that in this case, visual information has temporal superiority so auditory information can perceive slight difference because it is influenced by definite visual information and flash-induced sound illusion occurs. From this result, we can suggest that temporal illusion occurs from temporal ambiguity of stimuli rather than temporal resolution of modality.
Statistical modeling of expected rates of permanent hearing loss in newborn infants with data derived from the center for disease control
Authors: Goshorn Edward L. , Marx Charles G. , Ward Kimberly , Paterson Marietta
Published: October 2015

The Center for Disease Control (CDC) began gathering data on Universal Newborn Hearing Screening (UNHS) in 1999 and had data from all states and territories by 2005. The purpose of UNHS is to identify permanent hearing loss (PHL) in infants and make referrals for intervention. Health-care professionals may use CDC data to monitor the effectiveness of screening/diagnostic programs. Effective monitoring may designate whether or not an “expected” number of infants has been identified for a given birth rate. However, because the incidence of PHL in newborn infants is so low (nine-year CDC average across all states and territories equals 0.0013), a relatively large number of infants may be screened before the first occurrence of PHL. Therefore, there is legitimate concern that true positives will be missed due to a high rate of true negatives. Clinically useful models for comparing observed to expected data are needed. CDC data from 2005 to 2013 were used to set boundaries for binomial and negative-binomial distributions. These derived distributions were used to produce tables/graphs showing expected values and confidence intervals for an appropriate range of incidences and quantity of infants screened. The authors also offer actions to pursue if observed data vary significantly from models.
Efficient algorithm and localization experiment on spherical microphone array recording and binaural rendering
Authors: Liu Yu , Xie Bosun , Mai Haiming , Chen Jiayan
Published: October 2015

Spherical microphone array recording and binaural rendering (SMABR) is a novel spatial sound technique, which records spatial information of sound field, transfers to dynamic binaural signals, and then renders via headphone. To improve the computational efficiency of SMABR, the present work proposes a PCA-based (principal component analysis) algorithm for dynamic binaural synthesis from the beamforming outputs of spherical microphone array, in which only 33 pairs of sharable filters are required. Incorporated the proposed algorithm, a PC-based SMABR system consisting of a 64-channel spherical microphone array, an electromagnetic head-tracker, and a headphone is established. A virtual source localization experiment is carried out to evaluate the system and algorithm. Results indicate that the system yields reasonable localization performance within a target virtual source region near the horizontal plane. However, larger localization error is also observed for high elevation above 30 degrees or low elevation below -30 degrees. Localization error at high or low elevation is caused by the spatial aliasing error of spherical microphone array at high frequency, which spoils the spectral cue for elevation localization. Therefore, further improvement on spherical microphone array recording is needed. [Supported by the National Natural Science Foundation of China, Grant No.11174087.]
Our musical brain: Uncovering the neurophysical activation mechanism behind human perception of acoustics
Authors: Arosemena Ott Garrett W. , Blazey Tyler , Mitra Anish , Snyder Abraham Z. , Raichle Marcus E.
Published: October 2015

If, in fact, neuronal activity patterns in the brain are dominantly driven by external forces and environmental stimuli (Hasson et al. 2004), rather than individual variation, music, and certain musical features, should elicit directly correlated neuronal responses across specific structures of the brain—effects as strong as that examination and analysis of brain activity in one subject could accurately predict activations in another (brain). Importantly, locating areal responses and activity patterns to musical stimulation could uncover novel information as to brain network functions, as well as yield insight into the neural foundations of the creative mind. Subjects, comprised of highly trained (HT) classical musicians (St. Louis Symphony) undergo functional Magnetic Resonance Imaging (fMRI) blood-oxygenation-level-dependent (BOLD) scanning to map neuronal activity triggered by intervals of music (Haydn Symphony No. 3), silence, and noise. Observed activation included the auditory, posterior cingulate, and visual cortices. The posterior cingulate cortex, a central node in the brain’s Default Mode Network, has been strongly implicated in associations with episodic memory retrieval, working memory performance, human awareness, and several intrinsic control networks. The visual cortex is responsible for processing visual information; such activation may affirm the neuro-physical manifestation of HT performers’ staple sensualization of music—music experienced as color, flavor, feeling, mood, etc.
Robust analysis of sound field reproduction by ambisonics based on singular-value decomposition
Authors: Rao Dan , Xie Bosun
Published: October 2015

Ambisonics is a series of spatial sound systems with flexible loudspeaker configuration, which aims at reconstructing physical sound field in local region. Robustness of Ambisonics reproduction, which reflects the sensitivity of reproduced sound field to small errors, such as loudspeaker gain mismatch, is an important performance of sound reproduction. Condition number is generally used as an index to evaluate the robustness on whole, but this is insufficient because the robustness of reproduced sound field may be related to the target reproduction direction. To gain insights into the detail feature of robustness in Ambisonics reproduction, a method based on singular-value decomposition (SVD) is proposed to analyze reproduced sound field. The results indicate that the small singular values of transfer matrix and the proportion of Ambisonics coded vector projecting to the corresponding singular vectors dominate the robustness of Ambisonics reproduction. The robustness becomes worse only when such proportion of Ambisonics coded vector projection have relatively large energy. The proposed method is validated by simulating the sound pressure errors due to random mismatch of loudspeaker signals gain in some horizontal and spatial loudspeaker configurations. [Work supported by the National Natural Science Foundation of China, Grant No.11174087, and the State Key Lab of Subtropical Building Science, South China University of Technology, Grant No. 2014KB23.]
Elasticity Nonlinear Diagnostic method for crack detection and depth estimation
Authors: Le Bas Pierre-yves , Anderson Brian E. , Remillieux Marcel , Pieczonka Lukasz , Ulrich Timothy J.
Published: October 2015

In some Non-Destructive Evaluation techniques, detecting a crack is only the first step. Some applications like monitoring of used nuclear fuel canister also requires the characterization of the orientation of the cracks if any exist. Here, we show experimental results that expand the Time Reversal Elasticity Nonlinear Diagnostic method (TREND) to obtain the crack depth and orientation information. TREND is based on using time reversal to focus energy at a point of interest and then quantifying the nonlinearity at this point. By varying the frequency of the focal signal, one can interrogate different depth of the material, therefore getting access to information about the penetration depth of a crack. We will also show how Time Reversal can be used to select the orientation of the focus wave to any desired direction and how this, in turn, allows measuring different nonlinear responses according to this orientation and how this could be used to determine the orientation of cracks. [This work was supported by the US Department of Energy via the used fuel disposition campaign of the nuclear energy program.]
Human spoken language diversity and the acoustic adaptation hypothesis
Authors: Maddieson Ian , Coupé Christophe
Published: October 2015

Bioacousticians have argued that ecological feedback mechanisms contribute to shaping the acoustic signals of a variety of species and anthropogenic changes in soundscapes have been shown to generate modifications to the spectral envelope of bird songs. Several studies posit that part of the variation in sound structure across spoken human languages could likewise reflect adaptation to the local ecological conditions of their use. Specifically, environments in which higher frequencies are less faithfully transmitted (such as denser vegetation or higher ambient temperatures) may favor greater use of sounds characterized by lower frequencies. Such languages are viewed as “more sonorous.” This paper presents a variety of tests of this hypothesis. Data on segment inventories and syllable structure is taken from LAPSyD, a database on phonological patterns of a large worldwide sample of languages. Correlations are examined with measures of temperature, precipitation, vegetation, and geomorphology reflecting the mean values for the area in which each language is traditionally spoken. Major world languages, typically spoken across a range of environments, are excluded. Several comparisons show a correlation between ecological factors and the ratio of sonorant to obstruent segments in the languages examined offering support for the idea that acoustic adaptation applies to human languages.
Loudness and noise rating: How may standardization bridge the gap between science and engineering?
Authors: Völk Florian
Published: October 2015

Current noise regulations and standards, in Europe and to some extent also elsewhere, are primarily based on A-weighted sound levels. Most perceptual aspects are—if at all—taken into account by additional correction levels, for example, punishing tonality or impulsive content. On the contrary, instrumental loudness-prediction methods have been available for more than half a century and were first standardized 40 years ago. Against this background, the question arises why loudness—regardless of being calculated according to Zwicker or Moore and Glasberg—has not yet been accepted more widely in the field of noise control and related standardization. This contribution attempts to raise some possibly influential aspects, and to discuss them in the light of next-generation loudness standards. Advantages of stationary and time-varying loudness predictions over corrected weighted levels will be discussed and contrasted with potentially contradicting arguments. The discussion is primarily intended to provide arguments for the selection of future loudness-prediction standards. However, also a broader perspective is taken, looking at interrelations with other standards, algorithmically and regarding limiting values.
Near-field acoustical array measurements of an impinging supersonic jet
Authors: Gee Kent L. , Neilsen Tracianne B. , Torrie Darren K. , Akamine Masahito , Okamoto Koji , Teramoto Susumu , Okunuki Takeo , Tsutsumi Seiji
Published: October 2015

Impingement significantly alters the rocket plume in the near-launch pad environment, which in turn affects the acoustic radiation. Prior laboratory measurements of an unheated, Mach 1.8 ideally expanded jet impinging on 45-degree inclined flat plate were carried out using a microphone that was moved within a relatively dense grid [Akamine et al., AIAA J. 53, 2061–2067 (2015)]. A multi-institution collaboration by the authors was begun in order to conduct array measurements of the acoustic radiation from both impinging and free jets. Measurements comprised a total of 42 measurement channels located within 40 nozzle diameters. An array of two-dimensional microphone probes was placed so as to examine the transition from the hydrodynamic near field to the acoustic radiation. A scanning linear array of microphones and a stationary polar array were also designed to enable beamforming, cross correlation, and partial field decomposition. This paper describes the jet facility, experiment design, and initial analyses conducted on the data collected. [Measurements supported by the Japanese Society for the Promotion of Science.]
Spatiotemporal correlation of high-performance military aircraft jet noise
Authors: Harker Blaine M. , Neilsen Tracianne B. , Gee Kent L. , Wall Alan T. , James Michael M.
Published: October 2015

Correlation analyses of pressure measurements on a ground-based array of microphones of noise from a tethered high-performance military aircraft provide insights into the sound field variation with position and engine conditions which are fundamental in the continued development of more complete jet noise models. Time-scaled, single-point (auto)correlation functions confirm that to the side of the nozzle exit, the temporal correlation envelope decays very rapidly, whereas the envelope decays more slowly in the maximum radiation region and farther downstream. Two-point space-time (cross) correlation functions confirm that noise from a single engine operating at intermediate power is more similar to that from heated, laboratory-scale jets, whereas additional features seen at military power and afterburner are unique, including a feature which is likely related to the dual directivity lobe observed in the far field of military aircraft. A complementary coherence analysis provides estimates of spatial coherence lengths as a function of frequency and location. Field coherence lengths are utilized in analyzing coherence lengths of equivalent source distributions obtained from applying DAMAS-C to the ground-based array data. The cumulative results of these investigations provide a full-scale military jet noise benchmark that should be considered when evaluating laboratory-scale jet studies and simulations of jet noise.
Inclusion of a ground-reflecting plane in wavepacket modeling of military jet noise
Authors: Neilsen Tracianne B. , Gee Kent L. , James Michael M. , Harker Blaine M.
Published: October 2015

Equivalent source models for high-speed jet noise are intended to represent the acoustic properties of the turbulent mixing noise. A wavepacket ansatz previously applied to obtain equivalent sources from anechoic laboratory measurements is modified to include both a direct and image complex pressure representation of the source to model the presence of a ground-reflecting plane. This is important for modeling the sound field at maintainer and flight deck personnel positions because the interference effects caused by ground-reflected propagation paths significantly influence the sound levels and vary with frequency and location. The ability of the direct-plus-image wavepacket model to yield the interference patterns observed across large planes of data (2 m tall by 23 m long) measured near a high-performance military aircraft is evaluated. In particular, the variation in the nulls of the sound pressure level across the planes as a function of frequency predicted by this wavepacket model are compared to the measurements between 4 and 25 m from the engine nozzle exit. Comparisons with previous work based on a Rayleigh-distributed source amplitudes are also provided. [Work supported by the Office of Naval Research.]
Speech perception and spoken word recognition in young children
Authors: Edwards Jan , Mahr Tristan
Published: October 2015

Recent studies have found that expressive vocabulary size predicts spoken word recognition in young children. Children with larger vocabularies recognize even highly familiar words more efficiently than their peers with smaller vocabularies (Fernald et al., 2006). Furthermore, lexical processing efficiency at 18 months predicts future vocabulary size up to 8 years of age (Fernald et al., 2013; Marchman & Fernald, 2008). However, these studies did not include any measures of speech/language development beyond vocabulary size. We discuss the results of several studies that included multiple measures of speech and language development as well as measures of the home linguistic environment (using LENA, Ford et al., 2008). One experimental task assessed children’s online responses to correct productions of familiar words, to mispronunciations of these words, and to nonwords using eye-tracking. We found that speech perception was a better predictor of lexical processing efficiency than expressive vocabulary size. Furthermore, the number of conversational turns between children and their caregivers also predicted how quickly children looked at unfamiliar objects when they heard nonwords. Implications of these results are discussed. [Research supported by NIDCD grant 02932.]
The influence of gender identity on children's production of sibilant fricatives
Authors: Munson Benjamin
Published: October 2015

Phonetic differences between men and women's speech are the consequence of sex-related variation in the anatomy of the speech-production system, as well as learned behaviors specific to particular languages and to specific social and cultural contexts. Children learn socially and culturally specific gendered phonetic variants concurrent with developmental changes in the vocal tract which give the child an increasing capacity to produce systematic phonetic variation. The research in this presentation is part of a larger project examining phonetic variation in 5–13 year old boys with gender dysphoria (GD). This presentation focuses on the acoustic characteristics of /s/, which was chosen because it is the locus of a great deal of gender-related phonetic variation that appears not to be the consequence of sex differences in vocal-tract size and shape. Preliminary analyses of a subset (n = 30) of talkers from a corpus of 5 to 13 year old children (n = 104, including boys with GD and boys and girls without GD), found that boys with GD produce more [θ]-like /s/ tokens than boys without GD in single words. This talk presents the results from the entire corpus, which allows for a more robust analysis of the influence of gender identity on children’s fricative production.
Simulating the lateral line with low-frequency nearfield acoustic holography based on a vector hydrophone array for short-range navigation in littoral waters
Authors: Ziemer Tim
Published: October 2015

Fish use the lateral line system to detect swimming objects within a range of a few body lengths to avoid collision. This is achieved by detecting particle velocity and acceleration with receptors which are distributed all over the skin. In this work, this principle is imitated by means of a hydrophone array detecting particle accelerations. In a two-dimensional simulation setup, a dipole source is detected in presence of high-level noise and a disturbing source. This is achieved by a hull mounted vector hydrophone array applying low-frequency nearfield acoustic holography and an adaption of minimum energy method which simulate the lateral line. Noise is added to simulate decorrelated signals—like ambient noise and reverberation—whereas a disturbing dipole source creates highly correlated disturbing signals at the hydrophone positions which is typical for early reflections and sound sources outside the detection area. At the hydrophone array the noise is up to almost 70 dB louder than the radiated source signal. Despite these difficult conditions the proposed method localizes the source reliably within the range of a few array lengths. The system could be implemented in vessels for short-range navigation in coastal and littoral areas or underwater vehicles for mine deployment and harbor construction works.
New perspectives in Amazonian bird vocal behavior
Authors: Silva Maria Luisa
Published: October 2015

Neotropical region are known for its huge avian diversity and for the dominance of Sub-oscine or Tyranni passerines species. These species diversity are reflected in vocal communication and we will present here two examples of Brazilian Amazon forest of Tyranni species. Although the Tyranni are known for presenting a stereotyped song compared to Oscine passerines, we have found a species with a complex calls repertoire and other with a distinguished individual variation. The study area is the Ecological Park of Gunma, Santa Bárbara, Pará, Brazil, 50 km north of Belém. We performed playback experiments to define the vocalizations of Rusty-margined flycatcher Myiozetetes cayanensis, species that presents a complex repertoire of 15 different vocalizations, including a complex duet song. We also studied Lipaugus vociferans, a lekking bird, in which males perform conspicuous vocalizations in aggregations. We have analyzed songs of 19 individuals from six leks, considering the physical parameters (frequency bandwidth and temporal parameters) of the species-specific song. The results showed that it is possible to differentiate the individuals by song. These differences can represent an important function in individual recognition inside or between leks. These results show the necessity to investigate the high diversity of behavior in tropical habitats.
Does vocal learning accelerate acoustic diversification? Evolution of contact calls in Neotropical parrots
Authors: Araya-Salas Marcelo , Medina-Garcia Angela , Wright Timotthy
Published: October 2015

Learning has been traditionally though to accelerate the evolutionary change of behavioral traits. We evaluated the evolutionary rate of learned vocalizations and the interplay of morphology and ecology in the evolution of these signals. We examined contact calls of 51 species of Neotropical parrots of the tribe Arini from recordings obtained in Central and South America. Parrots are ideal subjects due to their wide range of body size and habitats and their open-ended vocal learning that allows them to modify their calls throughout life. We estimated the evolutionary rate of acoustic parameters of parrot contact calls and directly compared them to those of morphological traits and habitat. We also evaluated the effect of body mass, bill length and vegetation density on acoustic parameters of contact calls while controlling for phylogeny. Evolutionary rates of acoustic parameters did not differ from those of our predictor variables except for spectral entropy, which had a significantly slower rate of evolution. We found support for correlated evolution of call duration, and fundamental and peak frequencies with body mass; and of fundamental frequency with bill length. We demonstrate that parrot contact calls, which are learned acoustic signals, show similar evolutionary rates to morphological traits. This is the first study to our knowledge to provide evidence that change through cultural evolution does not necessarily accelerate the evolutionary rate of traits acquired through life-long learning.
Simulation of shear wave elasticity imaging including speckle and refraction effects
Authors: McAleavey Stephen A. , Langdon Jonathan H.
Published: October 2015

We present an overview of, and results from, a GPU-accelerated, 3D finite-difference time-domain acoustic radiation force impulse (ARFI) shear wave elasticity imaging (SWEI) simulator recently developed in our laboratory. The simulator allows modeling of the ultrasound “push” beam used to generate the shear wave, propagation of the shear wave in a viscoelastic, inhomogeneous medium, and simulation of ultrasound tracking of the shear wave. Spatial variations in both the ultrasound and shear wave speeds can be included to model ultrasound beam refraction errors and shear wave reflection and refraction by inclusions. Speckle has been shown experimentally to induce distortions in the apparent shape of a tracked shear wave, as well as biases in shear wave arrival time estimates used to generate shear wave speed images. A complete simulation of fully developed speckle captures this speckle bias effect but is time consuming. We present a dominant-speckle simulation approach that allows realistic modeling of the speckle-noise induced noise observed in videos of shear wave propagation in distributed speckle targets, and of artifacts in shear wave speed images. Matched simulation and phantom images of uniform and spherical inclusion targets are presented to demonstrate the ability of the simulation to capture key effects.
Numerical simulations of ultrasound-induced deformation of the lung surface
Authors: Patterson Brandon , Johnsen Eric
Published: October 2015

Ultrasound-induced lung hemorrhage remains the only known bioeffect of non-contrast, diagnostic ultrasound (DUS) found to occur in mammals. However, a fundamental understanding of the ultrasound-lung interaction is still lacking. In this study, we numerically simulate the deformation of the lung surface when subjected to clinically relevant pressure waves. We model the lung as air and the surrounding tissue as water. The two-dimensional, compressible Navier-Stokes equations are solved using a high-order accurate finite volume scheme. We first consider an air-water interface with a small sinusoidal perturbation and study the growth of the perturbations when subjected to a planar waveforms consisting of a step change in pressure. Scaling laws relating the waveform properties to the interface deformation rate are proposed for this simple case. Simulations with DUS waveforms indicate that the interface deformation depends on the unsteady nature of the wave. Preliminary analysis suggests that the initial interface deformation is driven by baroclinic vorticity deposited along the perturbed interface, and that the resulting stresses and strains are a possible candidate causing bioeffects.
Acoustics of finite Bessel tractor beams
Authors: Mitri Farid G.
Published: October 2015

Surprises and counterintuitive effects occurring in physical phenomena rank high on the list of things that make science discoveries a source of perpetual excitement. Some examples illustrated here include, (i) the effects of attracting (i.e., pulling) a spherical particle placed in the field of a Bessel acoustical beam of progressive waves back towards the radiator’s surface [Mitri, “Single Bessel tractor-beam tweezers,” Wave Motion 51, no. 6, pp. 986–993, 2014], (ii) suppressing some of the sphere’s resonances [Mitri, “Near-field acoustic resonance scattering of a finite Bessel beam by an elastic sphere,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 61, no. 4, pp. 696–704, 2014], (iii) and the emergence of a “negative radiation torque,” meaning that an incoming high-order Bessel vortex beam with a positive topological charge (known also as the order of the beam) would rotate a viscoelastic sphere in the opposite sense of the beam handedness [Silva et al., “Radiation torque produced by an arbitrary acoustic wave,” Europhys. Lett., 97, art. no. 54003, 2012]. Results and numerical predictions illustrate the analysis and extensions to other geometries, such as rigid oblate and prolate spheroids [Mitri, “Axisymmetric scattering of an acoustical Bessel beam by a rigid fixed spheroid,” http://arxiv.org/abs/1505.06754v3, ibid. "Acoustic radiation force on oblate and prolate spheroids in Bessel beams,” Wave Motion, 57, pp. 231–238, 2015] are also mentioned.
A stochastic inverse solution for functionally graded acoustic layered metamaterial validation
Authors: Reed Heather , Cipolla Jeffrey , Murray Patrick
Published: October 2015

Functionally graded acoustic metamaterials (FGAMs) can be designed to have specific waveguide properties. In sonar applications, FGAMs can be tailored to resist incident wave reflection. As these materials do not exist naturally, they must be fabricated by gradually layering manufactured, resulting in a (usually smooth) variation of properties. Validating material properties of FGAMs is difficult with conventional tests, as the distribution of material properties over the layered structure results in a non-unique solution if typical data (e.g., compressive strain) is measured. This talk will demonstrate an approach to characterize the functionally graded material properties by parameterizing how the functionally graded material changes throughout the specimen. Experiments designed to minimize the uncertainty surrounding the FGM model parameters are formulated and evaluated numerically. The FGM model parameters are estimated by Markov chain Monte Carlo so that a probability distribution surrounding each parameter is recovered. Probability distributions enable uncertainty quantification (UQ) surround the validated material parameters. UQ is important as uncertainty surrounding the parameter results directly translates into uncertainty surround the FGM performance. The approach is verified by bootstrap analyses of known FGAM distributions.
The clarinet: Past, present, and future
Authors: Coyle Whitney L.
Published: October 2015

The modern clarinet is the result of several hundreds of years of research and craftsmanship. This paper will discuss where the clarinet has been acoustically by studying some input impedance spectrum characteristics of historical instruments (the Baroque Chalumeau, 13-key, etc.). The paper will then present where we are at present—focusing on the same measurement information for a full Boehm system (multiple models of Bb clarinets) and a comparison of the modern French vs. German system clarinet. Finally, a few words will be given on the possible future of the instrument—where we are going, what are we doing to continue improving the instrument's quality and playability.