bluuebunny/crossref_metadata_2025 huggingface dataset:
Complex masking scenarios in Arctic environments
Authors: Sills Jillian , Reichmuth Colleen , Southall Brandon L.
Published: November 2013

Critical ratios obtained using octave-band noise and narrowband signals provide a useful first approximation for understanding the effects of noise on hearing. When considering realistic listening scenarios, it may be necessary to examine the effects of spectrally complex, time-varying noise sources on an animal’s ability to detect relevant signals. In the case of Arctic seals, the increasing prevalence of seismic exploration makes an examination of masking by impulsive sounds particularly relevant. However, the characteristics of received sounds from airgun operations vary dramatically depending on the seismic source, environmental parameters, and distance. In order to determine the potential for auditory masking by airguns, we developed a paradigm to quantify the influence of spectral and temporal variations in typical seismic noise on signal detectability. This method calls for calculation of detection probabilities for seals listening for the same signal embedded at different time windows within a background of distant airgun noise. We believe this approach will enable an experimental assessment of masking potential by impulsive noise as distance between the receiver and source is increased. Such an assessment will aid in determining the extent to which standard critical ratio data can be reasonably applied in complex masking scenarios. [Work supported by OGP-JIP.]
Characterization of the available feedback gain margin at two device microphone locations, in the fossa triangularis and Behind the Ear, for the light-based contact hearing device
Authors: Levy Suzanne C. , Freed Daniel J. , Puria Sunil
Published: November 2013

Assistive devices compensate for hearing impairment by amplifying sounds with gain, which is limited by acoustic feedback. The light-based Contact Hearing Device (CHD) provides amplification to 10 kHz by mechanically vibrating the umbo with a wireless Tympanic-Contact Actuator (TCA). Driving the eardrum mechanically generates a pressure wave, which travels laterally down the ear canal and produces feedback. Placing the microphone in the fossa triangularis (FT) may preserve more natural acoustic cues than the BTE location, although it may reduce available feedback gain margin (FGM). Thirteen subjects with bilateral mild-to-severe hearing impairment were fit with CHDs (26 ears). The TCA was driven with light-pulses and the feedback pressure was measured at the FT and above the pinna at the BTE microphone locations. The mean FGM varied from 32 to 48 dB and 38 to 60 dB for the FT and BTE microphone locations, respectively. FGM was lowest in the 3–5 kHz range and highest at about 7 kHz (below 1 kHz FGM is not measurable). The STD of FGM varied from 5.3 to 13 dB due individual anatomies. A microphone at the BTE has 6 to 12 dB additional FGM over the FT location, and allows a broader inclusion range to fit patients with amplification to 10 kHz.
Crying for help: The Frye hearing and forensic acoustic analyses in State of Florida vs George Zimmerman
Authors: Yonovitz Al , Joe Herbert , Yonovitz Joshua
Published: November 2013

Neighborhood watch volunteer George Zimmerman observed suspicious activity and called police. In minutes, he and Trayvon Martin were in an altercation when Mr. Zimmerman shot and killed Trayvon Martin and claimed self defense. The State’s audio experts evaluated the 9-1-1 audio recordings to determine who spoke which background phrases, if any. A Frye hearing is where the court determines the reliability and admissibility of an expert’s opinion by determining whether an expert’s methodologies are generally accepted within the relevant scientific community. The judge in this case ruled that the State’s two audio experts would not be permitted to testify during the trial. While the judge found the “aural perception and spectral analysis... are sufficiently established to have gained general acceptance within the scientific community,” she took exception to how they were applied in this case. This case provided a venue and forum for opinions on voice analysis, methodologies, standards, and the quality required of evidentiary audio for determination of speaker identification and elimination. Positions taken by witnesses, a critique of the Frye Hearing and the scientific basis for witness and legal conclusions will be discussed.
Classification of affricate burst place in consonant-vowel contexts in English
Authors: Lee Jung-Won , Kang Hong-Goo , Choi Jeung-Yoon
Published: November 2013

This study investigates characteristics of affricate burst place of articulation compared with the bursts for the three places of articulation for stops (labial, alveolar, and velar) in English. The data comprise consonant-vowel tokens in the TIMIT corpus. To assess which stop place of articulation may be used to simultaneously model affricate bursts, Jensen-Shannon divergence measures are found for probability distributions of acoustic-phonetic features. In addition, we conduct classification experiments using combinations of acoustic-phonetic features and Mel-frequency cepstral coefficients (MFCCs), to see how well affricate burst place is classified using models for the three stop places. The experimental results show that although affricate place is similar to the alveolar place of articulation for stops, a separate post-alveolar place for affricate burst provides a better model. The results suggest that a separate affricate place model will be useful in a feature-based speech recognition system that explicitly detects place of articulation for consonants.
Acoustic features mediating height estimation from human speech
Authors: Morton John , Sommers Mitchell , Lulich Steven , Alwan Abeer , Arsikere Harish
Published: November 2013

The current experiment was aimed at providing the first direct evidence regarding the role of subglottal resonances in height discrimination. Past research has investigated whether or not listeners are able to discriminate which of two talkers is taller (Rendall et al., 2007), but has not established what parameters of the acoustic speech signal listeners use to distinguish speaker height. In the current study, we examined the role of subglottal resonances in height discrimination. Subglottal resonances generally refer to resonances of the lower airways starting in the lungs and terminating at the glottis. Subglottal resonances would be a good candidate for use in height estimation because they remain relatively stable across vowels and are relatively unaffected by other factors influencing the supra-laryngeal vocal tract; instead they are influenced nearly exclusively by the lower airway acoustic properties. Listeners participated in two tasks, the first task was a two-alternative forced choice (2AFC) height discrimination test, in which listeners heard sentences produced by two talkers of the same gender and were asked to determine which of the two was the tallest. The second task involved listening to five talkers (all same gender) sentences, and then ranking those individuals from tallest to shortest. Findings indicate that listeners are able to discriminate and rank speakers heights better than chance, and the role of subglottal resonances will be reported.
Sociolinguistic perceptions of Californian /æ/ backing
Authors: D'Onofrio Annette
Published: November 2013

This paper investigates perceptions of a feature of the “California Vowel Shift” (Eckert, 2004): the backing of the TRAP vowel. The present study probes whether or not Californian and non-Californian listeners exhibit knowledge of TRAP backing's dialectal patterning in perception. An American English speaker's TRAP vowel was manipulated to create a 9-step continuum from /a/ to /æ/ in a sentence frame. 144 native U.S. listeners heard one of these steps, accompanied by orthographic information about the word spoken (e.g., the word was explicitly given as “blocked” or “blacked"). Listeners provided social categorizations of the speaker. Listeners were more likely to categorize the speaker as Californian when presented with TRAP orthography (e.g., “blacked") paired with a token on the continuum that was closer to /a/. 60 listeners participated in a phoneme categorization task using the same manipulated stimuli. When listeners were told that a speaker was from California, they were more likely to place the boundary between “blacked” and “blocked” closer to the /a/ end of the continuum than if told the speaker was from elsewhere. Together, these experiments indicate that listeners exhibit awareness of TRAP-backing's dialectal association with California, the top-down knowledge of which can affect lexical categorization.
Investigating the perception of relative speaker size using synthetic talkers
Authors: Barreda Santiago , Nearey Terrance M.
Published: November 2013

Several previous experiments have investigated the perception of speaker size by presenting listeners with acoustic stimuli that differ in average f0 and/or apparent vocal tract length (i.e., higher formant frequencies overall), and asking listeners to make judgments of relative or absolute speaker size. Typically, these experiments use stimuli with a fixed phonetic content so that the acoustic characteristics of the stimuli may be compared directly. In this experiment, listeners were presented with pairs of vowels produced by synthetic speakers with different apparent vocal tract lengths and the same f0, and were asked to make judgments of relative size. However, listeners were presented with either the same, or different vowels produced by the two speakers. In some cases, differences associated with varying vocal tract lengths were in conflict with differences arising from the formant patterns associated with the differing vowel categories (e.g., lower F1 and F2 for /u/ vs /e/). Results suggest that judgments of relative size are affected by both the vowel categories presented and the apparent vocal tract lengths of the synthetic speakers. That is, more than a simple (category-corrected) vocal tract length estimate is involved in making size judgments for an unknown speaker.
Speaker normalization in noisy environments using subglottal resonances
Authors: Arsikere Harish , Alwan Abeer
Published: November 2013

This work investigates the use of subglottal resonances (SGRs) for speaker normalization in noisy environments. Based on our previous work, a noise-robust algorithm is developed for estimating the first three SGRs from speech signals; it achieves robustness by factoring the short-term (or local) signal-to-noise ratio into the estimation process. The SGR estimates provided by this algorithm are refined by applying maximum-likelihood (ML) corrections, and are used in a non-linear frequency-warping technique that we recently developed. This SGR-based normalization (SN) scheme is evaluated on the AURORA-4 database in clean and noisy conditions. Using power-normalized cepstral coefficients (PNCCs) as front-end features, SN reduces the average word error rate by 8.7% relative to ML-based vocal-tract length normalization (VTLN). A fast version of SN (without ML corrections of SGR estimates) is also found to outperform VTLN (by 5.9% relative); it is computationally less complex than VTLN and hence a potential alternative for real-time applications.
Passive acoustic localization of small aircraft
Authors: Sedunov Alexander , Sutin Alexander , Salloum Hady , Sedunov Nikolay
Published: November 2013

Stevens Institute of Technology has built the Acoustic Aircraft Detection (AAD) system for the detection, tracking and classification of Low Flying Aircraft (LFA). LFA may be of concern as they have been used for illicit operations. The AAD consists of several nodes deployed in a wide area, where each node acquires signals from a cluster of five microphones. The calculation of the cross-correlation function of acoustic signals received by various microphone pairs is applied for finding the direction of the signal arrival. Fusion of time difference of arrival estimates from several pairs of acoustic sensors has resulted in the improvement of angle estimation accuracy. Triangulation of the direction of arrival estimates from two or more nodes was applied for determining the target position and altitude. Kalman filtering was used for smoothing the target tracks and decreasing the localization uncertainties. Software for predicting the performance was developed and was used to inform sensor placement in the field tests. The field tests were conducted with various kinds of LFA—single-engine, helicopters, and ultralights. Comparison of the acoustic tracking results with the GPS ground truth showed that the errors are similar to the theoretical predictions. [This work was funded by DHS S&T.]
Two case histories relating to the transmission of noise from mechanical equipment rooms to adjacent noise sensitive spaces
Authors: Coffeen Robert C.
Published: November 2013

Two recent noise control projects related to the reduction of noise from mechanical equipment rooms to an adjacent conference room and to an adjacent office. For both of these situations, the noise control procedures to be implemented involved the determination of the most significant noise transmission path; air borne noise transmitted through a concrete floor slab or structurally transmitted noise due to lack of proper chiller and pipe vibration isolation in the conference room case, or for the office case airborne noise transmitted through a wall constructed of gypsum wall board and flanking through common floor slabs or structurally transmitted due to lack of suitable pump and piping vibration isolation. A method for determining the most significant noise transmission path and the resulting noise reduction for these two cases will be described.
Case study: Isolation of a television production studio from airborne noise and ground-borne vibration
Authors: Reuter Eric L.
Published: November 2013

This project involved design of a 650-s.f. television and audio production studio in an existing historic building situated along a busy urban street with a subway tunnel below. Low background noise in the space was the primary concern, but the possibility of noise from music performance in the space interfering with nearby editing rooms and on-air studios was also considered. In order to satisfy all of the isolation requirements, the studio was constructed as a free-standing structure, supported by spring isolators on a new steel structure, within the existing building shell.
Upgrading secret military facilities—What is more important, acoustic design standards or acoustical performance?
Authors: Hale Marlund E.
Published: November 2013

The U.S. Department of Defense has developed acoustical performance standards that are to be achieved in the design and construction of meeting and conference rooms where sensitive and secret information will be discussed. These performance standards rely on published acoustical industry design data, which are readily available. The intention of these standards is to prevent sensitive and secret information from being heard, understood, or otherwise obtained by persons or devices that are not authorized to have access to such information. This paper presents design and field performance test results for new and renovated secret rooms that initially passed the acoustical design criteria and acoustical standard field tests, but failed to provide the desired secret level acoustical performance. Further investigations and research into partition, component, and building composite performance indicated that floors, walls, ceilings, doors, windows, and perimeter penetrations by conduit and HVAC ducting, which individually met the design standards and when installed meet the design standards, but as a composite did not provide the intended acoustical performance that would prevent unauthorized access to sensitive and secret information by persons or devices outside the designated perimeter. Reasons for certain performance failures are discussed and specific successful remedies are presented.
Disco dining: Where DJ culture meets high-end restaurants
Authors: Adams Tyler , Schwob Michael
Published: November 2013

Live DJs have quickly become a popular feature in the contemporary landscape of high-end restaurants. Many new establishments are sacrificing prime dining floor area so they may prominently feature a DJ booth. The Restaurateur's goal is not simply to entertain patrons and create ambiance but to use the name-recognition of DJs to draw customers and impart a sense of luxury and ”cool” cachet. Along with this cultural phenomenon comes an assortment of sound isolation and room acoustics issues that must be addressed to provide patrons with an enjoyable dining and listening experience and ensure the thumping dance music results in minimal impact to adjacent spaces and properties. In this talk, a number of such issues will be discussed using real-world problems and solutions from current high-end restaurants.
Forebrain processing of complex sounds: From mice to humans
Authors: Schreiner Christoph E. , Atencio Craig , Shih Jonathan , Hullett Patrick , Chang Edward
Published: November 2013

The decomposition and re-integration of complex sounds, such as speech, are at the core of auditory cortical processing. We will discuss the transformation of this process between subcortical and cortical stations from single-filter to multiple-filter models and its relationship to the structural organization of auditory cortex in animal models. We will compare findings of recordings from human superior temporal gyrus to speech sounds with the findings obtained from animal models and discuss potential implications for speech representation in primary and non-primary cortical areas.
Cortical representation of complex spectrotemporal features in songbirds
Authors: Kim Gunsoo , McLendon Helen , Doupe Allison
Published: November 2013

Mechanistic understanding of how the auditory cortex processes complex communication signals remains a challenge. With their rich vocal communication behaviors, songbirds can offer insights into this question. We investigated the neural representation of sound features in the cortical auditory areas of zebra finches. In the primary cortical area field L, our systematic mapping of spectrotemporal receptive fields revealed a highly organized representation in which sharpness of spectral and temporal tuning of sound is mapped along two separate anatomical axes. The clustering of temporally or spectrally selective neurons suggested that initial cortical filtering for basic perceptual qualities such as tempo and pitch occurs in a spatially organized and segregated manner. Moreover, using an information theoretic based technique, we are uncovering additional sound features beyond those represented by conventional spectrotemporal receptive fields. In field L, we find that many neurons encode a second feature that typically captures rapid spectral or temporal modulations overlapping the first feature. In the secondary auditory area CM, a major target of field L, we are discovering an emergent sensitivity to frequency stacks, prevalent in zebra finch vocalizations. Together, our data show a systematic and hierarchical mapping of sound features onto songbird cortical neurons.
Local field potentials in the big brown bat inferior colliculus track the flow of objects moving past the bat
Authors: Simmons James A. , Simmons Andrea M. , Warnecke Michaela , Barchi Jonathan R.
Published: November 2013

Echolocating big brown bats orient and guide their flight in cluttered environments by following narrow corridors through the maze of surrounding obstacles. When flying in clutter, the bat aims its head, broadcast beam, and external ears to the front, to determine whether the upcoming path forward is safe to enter. This stabilizes the surroundings relative to flight direction to make the flow-field passing by the bat on the left and right stand out from the scene. To examine the capability of the bat’s auditory system to follow the clutter as it moves past the bat, we recorded local field potentials (LFPs) from the inferior colliculus of anesthetized bats. We presented sounds that mimic FM biosonar broadcasts followed by clusters of echoes representing rows of objects moving past the bat. LFPs evoked by broadcast-echo sequences tracked the movements of the scene by registering arrays of echoes at latencies corresponding to echo delays. The limit for LFPs to follow multiple clutter objects is related to neuronal recovery times of several milliseconds. These data show that neural activity in the inferior colliculus represents dynamic changes in echo flow-fields that the bat would encounter in free flight. [Work supported by ONR and NSF.]
Different forms of auditory-vocal feedback control in echolocating bats
Authors: Metzner Walter
Published: November 2013

Auditory feedback from the animal’s own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Horseshoe bats exhibit a particularly well-developed form of auditory feedback. Their echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this “auditory fovea,” horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation behavior represents one of the most precise forms of sensory-motor feedback known. When examining the Lombard effect in horseshoe bats, we found that noise had different effects on call amplitude and frequency rises indicating different neural circuits and/or mechanisms underlying these changes. Both, amplitude and frequency rises were extremely fast and occurred in the first call uttered after noise onset, suggesting that, in contrast to Doppler-shift compensation, the Lombard effect did not require any auditory feedback. Bats also possess a large repertoire of communication calls, which differ greatly from those emitted during echolocation. We compared the variability of echolocation pulses and one common type of communication signal and found fundamentally different feedback mechanisms for echolocation and communication.
Catheter-based and endoluminal ultrasound applicators for magnetic resonance image-guided thermal therapy of pancreatic cancer: Preliminary investigations
Authors: Diederich Chris , Salgaonkar Vasant , Prakash Punit , Adams Matt , Scott Serena , Jones Peter , Hensley Daniel , Chen Henry , Plata Juan , Holbrook Andrew , Butts Pauly Kim , Sommer Graham
Published: November 2013

Ultrasound devices are being investigated for endoluminal and intraductal access for targeted thermal ablation or hyperthermia of pancreas under MR guidance and temperature monitoring. Simulations using patient-specific 3D models were developed for applicator design and development of treatment delivery strategies. MR-compatible devices were constructed for endoluminal (3-5 MHz planar or lightly focused rectangular elements, 12-mm OD assembly, expandable balloon), transgastric interstitial and intraductal (6-8 MHz multi-sectored tubular elements, 2-mm catheter) deployment. Micro-coils were integrated for active MR tracking of position and alignment. The proof-of-concept devices were tested in phantoms, ex vivo tissues, cadaveric porcine models, and in vivo animal models under 3T MR temperature imaging (MRTI). Results indicate endoluminal devices could ablate 2-2.5 cm depth from gastric wall for tumors of the pancreatic head, and multi-sectored tubular intraductal and interstitial applicators could ablate 2.3-3.4 cm diameter targets with directional control. Intraductal applicators could produce effective hyperthermia (>40 C) extending 15 mm radial. Customized tracking sequences could be used to locate 3D position of the applicators. Endoluminal, interstitial, and intraductal ultrasound applicators show promise for ablation or hyperthermia of pancreatic tumors. MR guidance can be employed for positioning these devices with active tracking coils and real time temperature monitoring. (NIH-P01CA159992.)
High-intensity focused ultrasound treatment of prostate cancer
Authors: Sanghvi Narendra T.
Published: November 2013

In the last decade, over 40,000 prostate cancer patients have been treated by HIFU systems in over 30 countries. These treatments have been conducted using two ultrasound image guided hifu devices—Ablatherm (EDAP, Lyon, France) and Sonablate® 500 (Focus Surgery, Inc., Indianapolis, IN). In addition, there is a shift in the management of prostate cancer from whole gland radical prostatectomy and radiation to focal treatment of prostate cancer. The focal treatment is guided by meticulous pretreatment imaging with multi-parametric MRI to accurately localize the index lesion. The MRI images are used to render 3D deformable model of the prostate gland and provide fusion of US and MRI to guide HIFU treatment resulting in reduced complications of rectal fistula, erectile dysfunction, and urinary incontinence. The results of the clinical studies indicate that patients with recurrent cancer post radiation can benefit from HIFU treatment. Both these devices are marketed in many countries and recently have submitted PMA applications to the FDA to receive clearance to market in the United States. Long term clinical results and status of HIFU devices will be presented.
Thermophone projectors using nanostructure materials
Authors: Dzikowicz Benjamin , Baldwin Jeffrey W. , Tressler James F.
Published: November 2013

Thermophone transducers fabricated from new nanoscale materials hold the promise of a new transducer technology for the Navy with no moving parts that operate over a broad frequency range and can be designed to be lighter and thinner than competing technologies. This potentially makes them ideal for use as high performance conformal projectors on autonomous underwater vehicles, submarines, and other small craft. Although thermophone devices have been understood for nearly a century, [Phys. Rev. 10, 22 (1917)], new nanostructure materials with extremely low heat capacities per surface area have recently become available which have the potential of greatly increasing their efficiency. Thermodynamic models show that certain surfaces, gasses, and enclosures will increase the acoustic efficiency. However each of these modifications of the base design has drawbacks as well. These will be discussed from a theoretical standpoint and results from laboratory testing will help to verify these hypotheses. [Work supported by NRL.]
Carbon nanotube thermoacoustic projectors for undersea vehicles
Authors: Zarnetske Michael R. , Blottman John B.
Published: November 2013

Renewed interest in the thermophone has developed with the recently demonstrated capability to manufacture carbon nanotube thin films and capacity to emit sound through the thermoacoustic effect. High fidelity broadband sound generation is attributed to the ultra-low heat capacity and low thermal inertia of these films. Motivated by the need for low-frequency, broad-bandwidth, compact sonar projectors to be embedded in the hull of unmanned sea vehicles or in the outer coating of a surface combatant or submarine as a conformal array, a team of researchers from Virginia Tech, The University of Texas at Dallas, and the Naval Undersea Warfare Center are evaluating these novel materials and devices both theoretically and experimentally. Analytical and numerical simulations support mechanical, thermal and acoustic experimentation. Correlated results will be presented. [Work supported by Office of Naval Research, code 321MS.]
Correlation analysis of military aircraft jet noise
Authors: Anderson Zachary , Harker Blaine M. , Gee Kent L. , Neilsen Tracianne B. , James Michael M.
Published: November 2013

Correlation analysis is useful in extracting spatiotemporal relationships between signals and can be used to examine features of near-field jet noise for source properties. Characteristic correlation envelopes determined by Harker et al. [J. Acoust. Soc. Am. 133, EL458 (2013)] can be used to relate correlation lengths to fine and large-scale turbulent structures. As an extension, cross-correlation shows spatial variation in jet noise and further reveals the transition between short (fine-scale) and long (large-scale) correlation lengths. These analyses are applied to a military jet dataset of a ground based linear microphone array positioned 11.6 m from the jet axis. Correlation analyses over multiple engine conditions and observation directions are reported. In particular, a maximum correlation coefficient greater than 0.5 exists over a range spanning multiple wavelengths in the region of greatest overall sound pressure level at military power. [Work supported by ONR.]
On the crest factor of noise from supersonic jets
Authors: Gee Kent L. , Neilsen Tracianne B. , James Michael M.
Published: November 2013

An important consideration in characterizing noise from heated, supersonic jets is the crest factor (CF). The large CF in high-speed jet noise is the result of a positively skewed probability density function for the waveform, which translates into infrequently occurring, large-amplitude positive peak pressures. Sufficient system headroom is required in the data acquisition system to provide an accurate representation of these peak pressures and thus avoid clipping or microphone saturation/distortion. But the question remains as to the importance of capturing the single largest pressure out of potentially millions of waveform samples or if a percentile-based CF is adequate. Measurements near a static tactical aircraft reveal CF increases with engine power, with the maximum CF directed upstream of the overall sound pressure level, and a maximum CF of 20 dB at full afterburner. Second, clipping of measured waveforms at different thresholds reveals that a CF definition based on the 99.99 percentile is sufficient to represent overall and band pressure levels to within 0.1 dB and waveform and time-derivative skewnesses to within ~1%. If an estimate of the time-derivative kurtosis is needed within 1% accuracy, then the 99.999 percentile CF is required for headroom estimates.
Noise reduction performance of wheel vibration absorbers
Authors: Nelson James T.
Published: November 2013

The noise reduction effectiveness of wheel vibration absorbers was evaluated at the Bay Area Rapid Transit System (BART). The vibration absorbers were fitted to the steel tires of aluminum-centered wheels. Wayside noise was recorded at tangent and curved track with resilient direct fixation fasteners, and under-car noise data were recorded throughout the system. Data were collected with and without wheel vibration absorbers installed. The wheel vibration absorbers had little effect on wayside and under-car noise at audio frequencies, though a minor reduction of noise at about 500 Hz was observed, suggesting a change in wheel dynamics. Third octave band noise reductions are summarized for on-board and wayside measurements.
Measurement of dynamic viscoelastic properties of flexible polyurethane foam under compression for application to seat vibration analysis
Authors: Kim Deokman , Yoon Won-Sok , Park Hyun-kyu , Kim Hak-Sung , Park Junhong
Published: November 2013

Supporting stiffness of the seat is one of the important components affecting dynamic characteristics recognized by a passenger. To analyze dynamic characteristic of seat for vehicles operating on various road conditions, the seat should be understood together with the oscillation due to road irregularity. In this study, the viscoelastic properties of flexible polyurethane foam under compression was measured and used in estimating the dynamic characteristic of seat analyzed as a simplified geometry. The beam transfer function method is used to obtain the dynamic properties of the foam under compression. The viscoelastic properties were obtained to the maximum compression level of 70%. The simple seat model was composed rigid base, edge blocks, elastic supports, and flexible polyurethane foam, and the method is used in the same way to obtain the dynamic support properties. The equivalent support stiffness was estimated on various locations on the seat, and the effects of each component such as the compression level, the foam type, and the stretch of elastic support were analyzed.
“Incubation of damage” state quantification in laminated composites and metallic alloys
Authors: Banerjee Sourav
Published: November 2013

In this presentation, a comparatively simple but efficient novel approach is proposed to quantify the “incubation of damage” state using scanning acoustic microscope (SAM). The proposed approach exploits the nonlocal micromorphic field theory to quantify intrinsic (multi-scale) damage state. Defying the conventional route of ‘bottom-up’ multi-scale modeling methods, a hybrid ‘top-down’ approach is presented, which is then correlated to ultrasonic signature obtained from composite and metallic alloy specimens. A parameter to quantify the incubation of damage at meso-scale has been identified in this paper. The intrinsic length scale dependent ‘parameter called ‘damage entropy’ closely resembles the material state due to fatigue, extreme environments, operational hazards or spatio-temporal variability, etc. The proposed quantification process involves fusion between micromorphic physics and high frequency ultrasonic. The proposed approach is validated through an experimental study conducted on sequentially fatigued glass-fiber reinforced polymer composites and Aluminum 5xxx aluminum alloy specimens. Specimens were characterized under scanning acoustic microscope (50 and 100 MHz). The imaging data and the sensor signals are characterized to quantify the incubation of damage state by a new parameter called ‘damage entropy.’
Assessing language acquisition from parent-child interaction: An event-related potential study on perception of audio-visual cues in infancy
Authors: Klintfors Eeva , Gustavsson Lisa , Schwarz Iris-Corinna , Gerholm Tove , Marklund Ulrika
Published: November 2013

This paper promotes a theory-driven model development of parent-child interaction. In our project, we identify, test, and simulate some of the fundamental components of speech, gestures, and social-emotional behaviors and the consequences they might have on child language development. Our theoretical position is part of the connectionist tradition; language acquisition is described to be an emergent consequence of the interplay between the infant and the ambient linguistic environment, including sensory information of all modalities. It is well known that speech comprehension and production are significantly influenced by the presence of co-speech gestures. These gestures may be articulatory in nature or hand/beat co-gestures that keep the rhythm of speech. However, since the extent of this integrated relationship is difficult to determine from behavioral research solely, studies addressing neural mechanisms that underlie cognitive processes and behaviors are of importance. This paper reports an electroencephalography/event-related potential (EEG/ERP) pilot study on children’s early perception of congruent versus incongruent audio-visual pairings (e.g., acoustic information matching vs not matching the articulation shown). Ultimately, it is our hope that understanding the integrated speech-gesture relationship may provide insights into how children allocate resources while speaking and help clinicians/teachers to better identify and treat children with developmental disorders.
Assessing language acquisition from parent-child interaction: An event-related potential study on perception of intonation contours in infancy
Authors: Gustavsson Lisa , Klintfors Eeva , Schwarz Iris-Corinna , Gerholm Tove , Marklund Ulrika
Published: November 2013

The aim of this paper is to present our multidisciplinary project to study parent-child interaction. The goal of the project is to identify, test, and simulate components of child and adult speech and gestures and the consequences they might have on child language acquisition. Since typical parent-child interaction is built upon both interlocutors’ intention-reading, responsiveness to joint-attention, and imitation of speech/gestures, we make video recordings along with recordings of speech data to grasp the integration of semantic and pragmatic aspects of language acquisition. The understanding of parent-child interaction benefits further from information on brain activation involved in speech processing. As a first step to achieve the project goals, an electroencephalography/event-related potential (EEG/ERP) study exploring children’s early perception of intonation contours involved in human interactions was performed. This paper discusses the characteristics of integration of multimodal social-emotional (speech, prosody, faces, posture) signals as part of the dynamics of communication in typically developing children. Possible application fields are social signal processing (SSP; an emerging research domain that aims to provide computers ability to understand human social signals), and improvement of diagnosis of late or atypical language development in pathologies that affect the dynamics of social interaction (such as autism spectrum disorders).
The role of orthographic information in the learning of allophonic variation
Authors: Yang Chung-Lin , Darcy Isabelle
Published: November 2013

Exposure to L2 orthography may facilitate learning a novel vocalic (e.g., Escudero et al., 2008) or tonal (Showalter and Hayes-Harb, 2013) L2 contrast. Yet it is unclear whether the benefit of orthographic information applies to the learning of L2 words involving allophonic variants. We investigated whether exposure to L2 orthography can help L2 learners establish a single lexical representation for words containing allophones. We used an invented language, with word-pairs of free variants (test condition) involving the vowel alternation [ɔ]-[u], both of which can be spelled as . In the control condition, vowel alternation [e]-[a] contrasted word meanings. In a word learning experiment, Mandarin and American English speakers were presented with words paired with pictures. In addition, one subgroup of participants saw the spellings when they heard the words, while another did not. Then, in a picture-auditory word matching task, participants who learned that the variants were allophonic were expected to link the two variants to one single picture in the test condition only, not in the control. A facilitative effect of orthography on the learning of free variation was observed for Mandarin speakers. This shows that orthography may help L2 learners establish a single lexical representation for allophonic variants.
Development of vowel spaces from age 21 to age 49 in a group of 8 talkers
Authors: Lutzross Auburn , Schuerman William , Sprouse Ronald , Gahl Susanne
Published: November 2013

We describe age-related change in speech during young to middle age adulthood using a new resource for phonetic and sociolinguistic analysis. This resource is based on the “Up” series of documentary films, showing a set of 11 individuals filmed at seven year intervals over a period of 42 years. We analyzed 67 sample utterances (minimum duration = 10 s), containing 4493 vowels produced by eight talkers, with the aim of understanding how vowel spaces change in young and middle-age adulthood, prior to physiological changes often observed in elderly talkers. We measured the first and second formants of each vowel token and analyzed several measures of vowel distribution in F1/F2 space: Euclidean distance from the talker's average F1/F2 (“dispersion”), within-category variability (intra-vowel dispersion), and vowel space area. Area of the vowel space was measured using averages of point vowels (/a/, /ae/, /i/, /u/), as well using the convex hull of all vowels. For some individuals, vowel spaces from age 21 to age 49 come to be more compact, in a manner that has previously been observed in elderly speakers. However, we also find considerable individual variability, with no clear age-related trend across speakers.
Energy efficient transmission policies in non-stationary underwater acoustic channels
Authors: Tomasi Beatrice , Preisig James C.
Published: November 2013

This work focuses on making underwater acoustic communications energy-efficient, by reducing the amount of unsuccessful transmissions. The approach is enabled by a priori information regarding the second order statistics of the channel quality. However, the non-stationarity of the physical processes that primarily influence the acoustic propagation makes both channel representation and identification challenging. Therefore, we first evaluate the different types of second order statistics of the underwater acoustic channel measured during two experiments, SPACE08 and KAM11, during which the same source and receiver hardware was employed in different environmental conditions. Then, we classify the different observed second order statistics estimated over a few minutes time intervals and propose suitably trained Markov models to represent the evolution of these different second order statistics. This channel representation is used to derive an optimal transmission scheduling that minimizes the number of transmissions required to deliver a given amount of information B by a given deadline T. In particular, we provide insights on how the structure of the optimal policy changes with the different observed behaviors of the second order statistics of the channel.
A relative-entropy approach to distributed passive detection
Authors: Mignerey Peter C.
Published: November 2013

There is currently much interest within the ocean acoustics community on using distributed sensor networks to monitor ocean properties. One such task is the application of distributed sensors to passive detection of weak acoustic sources. The joint likelihood detection ratio for a set of distributed sensors leads naturally to the comparison of relative entropy with a detection threshold. As a nondimensional additive measure of information, relative entropy enables data fusion among disparate kinds of sensors, e.g., acoustic and electromagnetic, and mitigates calibration issues. Furthermore, because relative entropy is an integral over probability densities of sensor outputs, it is insensitive to false alarms from transients. In this talk, the theory of relative-entropy detection will be presented, and the method illustrated using acoustic intensity data from hydrophones deployed by the Transverse Acoustic Variability Experiment (TAVEX). For the method to work, accurate estimates of the probability densities for noise and signal intensities must be obtained. For the TAVEX data, superior receiver operating characteristic curves are obtained when the noise and signal distributions are represented by log-normal distributions in comparison with gamma and nonparametric distributions. [Work supported by the Office of Naval Research.]
Ultrasonic measurements of suspended sediment concentrations at Harris Bayou, Mississippi
Authors: Carpenter Wayne O. , Kajdan Thomas A. , Goodwiller Bradley T. , Surbeck Cristiane Q. , Chambers James P. , Wren Daniel G. , Kuhnle Roger A.
Published: November 2013

The use of ultrasonic acoustic technology to measure the concentration of fine suspended sediments has the potential to greatly increase the temporal and spatial resolution of sediment measurements while reducing the need for personnel to be present at gauging stations during storm events. In collaboration with the USGS, a customized field deployable system was installed to monitor fine sediment particles, less than 100 micron in diameter, in suspension at Harris Bayou near Alligator, MS. Calibration measurements show good agreement between laboratory grade equipment and the new prototype system. The field unit consists of two immersion ultrasonic transducers measuring attenuation of 20 MHz acoustic signals propagated through suspended particles. The results of field prototype will be presented here.
Numerical study of the spatial and temporal variability of ambient noise in the coastal region east of Taiwan Strait
Authors: Chang Andrea Y. , Chen Chi-Fang , Lin Sheng-Fong , Wei Ruey-Chang
Published: November 2013

Noise soundscape represents the characteristics and spatial distributions of the ambient noise level under various noise source mechanisms. This is a significant index while describing an underwater acoustic environment, especially in the subjects related to marine mammal protection. Under the effects of topography, sediment, and oceanographic features, underwater soundscape varies with time and space. This paper focuses on estimating mean soundscape of wind driven noise and shipping noise and their spatial and temporal variability in the coastal region east of Taiwan Strait, which is the main habitat of the Sousa Chinensis. The ambient noise is studied numerically and local wind field and shipping density observed by Automatic identification Systems (AIS) are applied to generate noise source field. As for the ocean environment, the time varying/spatial dependent temperature profiles generated by the Taiwan Coastal Ocean Nowcast/Forecast System (TCONFS), which formulated on the basis of the Princeton Ocean Model, is used for water column variability, and both topography database and geo-acoustic database are used to describe the bottom. The modeling results demonstrate the temporal/spatial variability induced by ocean environment, manifested by measured data. [This work was supported by National Science Council of Taiwan and Bureau of Energy (Grant No.102-D0105).]
Acoustic mode coupling due to subaqueous sand dunes in the South China Sea: Extension of the adiabatic criterion to waveguides with bedforms
Authors: Chiu Linus , Reeder Davis B.
Published: November 2013

The large subaqueous sand dunes on the upper continental slope of the South China Sea (SCS) create a range-dependent ocean acoustic waveguide within which acoustic energy is expected to couple between propagating normal modes. Here, the criterion of adiabatic invariance is extended to the case of a waveguide possessing bedforms. The morphological features of the bedforms modeled in this theoretical and numerical investigation are based on echosounder observations of the SCS sand dune field during a research cruise in the spring of 2012 on the Taiwanese R/V Ocean Researcher 2 (OR2). Using the extended criterion for adiabatic invariance to examine mode propagation over these bedforms, results demonstrate that bedforms increase mode coupling strength such that the criterion for adiabatic propagation is exceeded for waveguides with small bedform amplitude to water depth ratios; increasing bedform amplitude enhances mode coupling. Physically, initially bottom-trapped mode 1 energy abruptly couples to higher adjacent modes, with most of the energy preferentially settling into a few select modes. The scattered energy fills the water column to near-surface depths downrange of the bedforms. Numerical simulations confirm the extended criterion parameterization. [This work was supported by National Science Council of Taiwan.]
Underwater navigation using an acoustic spiral wave front beacon
Authors: Dzikowicz Benjamin , Hefner Brian T.
Published: November 2013

A spiral wave front beacon consists of an array of transducers which produce a signal whose phase depends on the azimuthal angle at which it is received and a reference signal with constant phase [J. Acoust. Soc. Am. 131, 3748 (2012)]. A vehicle can determine aspect to the beacon by comparing the phase of the two signals. Progress in the development of this navigation technique will be discussed including results from experiments at Dodge Pond in Connecticut where an unmanned surface vehicle determined its aspect to within 10° by receiving signals from the beacon. Also, tests of a new spiral beacon design [J. Acoust. Soc. Am. 130, 2506 (2011)] in laboratory and underwater environments will be presented. Underwater experiments are performed at the Navy’s Seneca Lake facility in upstate New York using an UUV to record signals. Overall, these results demonstrate that intrinsic phase shifts in the beacon can be handled by signal processing at the receiving vehicle and that the spiral navigation technique is robust in reverberant environments. [Work supported by the Office of Naval Research.]